JPH0246417B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to signal transmission for transmitting signals between a device on a vehicle body and a steering operation board near a steering operation wheel, and in particular,
It relates to steering control board signal transmission that transmits digital signals such as FSK (Frequency Shift Keying) signals and analog signals such as audio signals on the same transmission line.

In a vehicle, the steering wheel is closest to the driver, and is also closest to the driver's hands, so in order to improve operability, it is necessary to install an operation board equipped with key switches for controlling on-vehicle equipment.
It is preferable to install it in the center of the steering wheel.

However, because the steering mechanism that transmits wheel rotation to the steering shaft is complex,
It is difficult to wire the signal cable that connects the operation board (steering operation board) installed in the center of the steering wheel and the fixed control unit. The applicant has developed a system (Japanese Patent Application No. 132926/1983) in which a slip ring and a brush are used to connect an operation board and a fixed control unit, and power and signals are transmitted through the line. Proposed. According to this, signals and power can be transmitted between the operating board and the fixed control unit without using a large number of lines.

By the way, when a wireless communication device is installed on the vehicle,
Since the communication device has to be installed at a considerable distance from the person making the call, such as the driver, the talking part such as the microphone is generally separated from the main body of the communication device to prevent noise from being transmitted from the surroundings. The talking part and the main body of the communication device are connected with a cord, and when communicating, the talking part is removed from the main body of the communication device and brought closer to the person making the call. However, when the driver wants to talk on the phone, he or she must hold a microphone or the like with one hand, which means that the driver must drive with one hand, which is dangerous. Even in a vehicle, it is the driver who has the most opportunities to talk on the phone, so
It is desirable to enable drivers to safely talk on the phone while driving.

Therefore, if the microphone is placed on the steering operation board, the microphone is close to the driver's mouth, so the driver can talk without having to hold the microphone in his hand. However, if you do so,
The signal from the keyboard is a digital signal,
Since the signal from the microphone is an analog signal, wiring between the steering control board and the fixed control unit is difficult. For example, if you try to transmit analog signals, digital signals, and power using separate transmission lines, you will need three transmission lines, but even if you use a mechanism that combines slip rings and brushes for this connection, The structure of the mechanism becomes quite complex.

The first object of the present invention is to place a microphone on the steering operation board to faithfully transmit the driver's voice to a fixed control unit.
A second purpose is to simplify the connection between the steering operation board and the fixed control unit.

In order to achieve the above object, in the present invention,
A microphone, an analog modulator for audio signals, and a digital modulator for key input signals are installed on the steering operation board, and an analog demodulator and a digital demodulator are installed on the fixed control unit side, and control is performed according to the output of the digital demodulator. and apply the output signal of the analog demodulator to a communication device, etc. The frequencies are set to different values for the analog modulation signal and the digital modulation signal, and these signals are placed on the same transmission line. The output end of the digital modulator is coupled to the transmission line via a capacitor, and a delay means, such as a capacitor, that delays the rise of the signal is connected to the output end of the digital modulator.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an embodiment device. 1st
This will be explained with reference to the figures. In this example, the steering operation board includes a constant voltage power supply 70, a microcomputer unit 80 (CPU1) that controls the steering operation board, and a key switch 9.
0, FSK modulation/demodulation circuits 100, 110, microphones MC1, MC2, differential amplifier DFA, FM modulator 95, two screen displays, i.e. monitor TV
It is equipped with TV1, TV2, tuners TU1 and TU2, distributor 190, etc.

The microphones MC1 and MC2 are placed facing the same direction (toward the driver's mouth) at a predetermined interval, and their output ends are connected to different input ends of the differential amplifier DFA. As a result, the sound applied to microphone MC1 and MC
Since the difference in the sound applied to the two is amplified by the DFA,
A large output can be obtained for sound coming from the direction in which MC1 and MC2 are arranged, that is, from the direction of the driver. In other words, noise from the side is canceled out, and only the signal corresponding to the driver's voice is greatly amplified and applied to the FM modulator 95.

In this embodiment, the control unit on the vehicle body side includes a constant voltage power supply 120, a microcomputer unit 130 (CPU 2), and an FSK modulation/demodulation circuit 15.
0,160, FM demodulator 170, telephone TEL, mobile device, that is, radio communication device TRX for telephone, branch connection circuit 180, amplifier AMP, speaker
SP, microcomputer unit 2 for display
00 (CPU 3), video rams V _RAM1 and V _RAM2 , modulators 210 and 220, a television camera TVC, a mixer 230, and the like.

The transmission path 250 includes a connection mechanism consisting of a slip ring SA1 and a brush BA1, and a slip ring SA1.
The steering operation board and the vehicle body are connected through a connection mechanism consisting of the brush BA2 and the brush BA2. On the steering operation board, FSK modulation/demodulation circuits 100, 110, FM modulation circuit 95, and distributor 190 are each connected to a transmission path via a capacitor, and a stabilized power supply circuit 70 is connected via electric coil L1. . On the vehicle body side, FSK modulation/demodulation circuits 150, 160, FM demodulation circuit 170, and mixer 230 are connected to a transmission line 250 via capacitors, respectively, and a power switch SW that operates in conjunction with a stabilized power supply 120 and an ignition key switch. One end is connected via electric coil L2.

Fig. 2a shows the vicinity of the driver's seat of a vehicle equipped with the device shown in Fig. 1, and Fig. 2b shows the appearance of the vicinity of the steering wheel. This will be explained with reference to FIGS. 2a and 2b. A telephone TEL is placed on the left side of the driver seat 1, and a speaker SP is placed in front of it. steering wheel 3
A steering operation board 4 is provided in the center of the steering wheel 3, which is placed above the steering wheel 3. The front panel 5 of the steering operation board 4 includes display screens for two monitor TVs TV1 and TV2, a rear confirmation key, a fuel key, a speed key,
The call/off key, telephone numeric keypad, hold key, clear key, etc. are exposed. In this embodiment, flat cathode ray tube display devices manufactured by Sony Corporation are used for the monitor televisions TV1 and TV2.

FIG. 2c shows a schematic mounting structure between the steering wheel 3 and the steering operation board and the vehicle body. This will be explained with reference to FIG. 2c. The support 38 is fixed to the support 41 and rotatably supports the gear 39. The gear 39 is fixed to the vehicle body. The support 41 is fixed to the steering shaft 40 and is attached to the steering wheel 3.
is connected to support 41. Support 41 rotatably supports gears 39 and 42.
43 denotes gears 43a and 4 having the same number of teeth at both ends.
3b, and is rotatably supported by the support 41. Gears 43a and 43
b mesh with gears 39 and 42, respectively. Steering operation board printed circuit board 44
And the operation panel 5 is fixed to the gear 42. The gears 39 and 42 have the same number of teeth. With this configuration, the steering wheel 3
The operation panel 5 etc. do not rotate with the rotation operation. That is, in the case of this embodiment, when the steering wheel 3 is rotated, the support 41 and the steering shaft 40 are rotated to perform a steering operation.
have the same number of teeth, so the relative movement amount (angle) between the support 41 and the gear 39 caused by the circular movement of the connecting member 43 due to the rotation of the support 41, and the relative movement amount between the support 41 and the gear 42 are as follows. are equal, gear 39 is fixed and gear 42
does not rotate relative to the gear 39, so even if the steering wheel 3 rotates, the operation panel 5 does not rotate.

The steering wheel 3 is equipped with two brushes BA1 and BA2 that are electrically connected to each other. The brush BA1 has one end in contact with a slip ring SA1 provided on the steering operation board side, and the brush BA2 has one end in contact with a slip ring SA2 provided on the vehicle fixed side.

Figures 2d and 2e show a slip ring.
The configuration near SA1 is shown in detail. The explanation will also be made with reference to FIGS. 2d and 2e. In this example, electromagnetic shielding is provided to prevent the S/N ratio from decreasing due to electromagnetic waves radiated from the slip rings SA1, SA2, etc. That is, the slip ring SA1 is installed in a recess of a resin insulator plate 51 having a ring-shaped recess with a predetermined width.
Conductor shield plates 52 and 53 are attached to surround the plate 51. The shield plate 53 has grooves 51a and 5 of the insulator plate 51.
It is fixed at 1b. The brush BA1 has a resin collar 54 attached to its tip, passes through the hole 53a of the shield plate 53, and is fitted with a compression coil spring.
It is constantly in contact with the slip ring SA1 due to the pressing force of SP1.

The shield plate 52 is electrically connected to the gear 42, and the shield plate 53 is electrically connected to the steering wheel 3, thereby grounding the vehicle body. Slip ring SA2 and brush
The vicinity of BA2 has a similar configuration, and two shield plates (not shown) in this area are grounded to the steering wheel 3 and steering shaft 40, respectively.

FIG. 3a shows the configuration of the electric circuit on the steering operation board. This will be explained with reference to FIG. 3a. The key switch 90 is a microcomputer
It consists of a large number of key switches connected in a matrix to three output ports P20, P21 and P22 of the CPU 1 and eight input ports DB0 to DB7. These key switch contacts are opened and closed by operating predetermined portions on the operation panel 5.

The FSK modem 100, 110 is a one-chip integrated circuit in this example, and its internal structure is shown in detail in FIG. 3b. 1
00 is an FSK modulator, and 110 is an FSK demodulator.
Note that Z shown inside the FSK modem 100, 110
1, Z2, and Z3 are counters having functions equivalent to those of Motorola's MC14040, MC14018, and MC14040, respectively. Other elements are
These include general D-type flip-flops, J-K flip-flops, NAND gates, and inverters.

The terminal CLOC is the input terminal of the clock pulse that determines the reference timing of transmission, and the terminal DIN is the input terminal of the clock pulse that determines the reference timing of transmission.
Value data input terminal, signal input terminal where terminal SW controls the output of FSK signal, terminal DOLC and
DOHA is a modulation signal output terminal, terminal SIN is an FSK signal input terminal, and SOUT is a demodulated binary data output terminal.

Terminal COLC of FSK modem 100, 110,
DIN, SW and SOUT are connected to ports P11, P10, ALE and TO of CPU1, respectively, and complementary output transistors Q1 and Q2 are connected to modulation output terminals DOLC and DOHA. Output lines from transistors Q1 and Q2 are connected to a transmission line leading to slip ring SA1 via a protective resistor R1 and capacitor C1. Also, between this output line and the ground line, there is a capacitor C2 with a relatively small capacity.
is connected. This capacitor C2 is for delaying the rise of the pulse signal.

In other words, when the FSK modulation output end is coupled to the transmission line 250 with the capacitor C1, the FSK modulation output end is connected to the transmission line.
A differential pulse is generated at the rise and fall of the pulse signal, but the rise of this differential pulse is rapid, and the frequency of the harmonics of this pulse signal extends to the frequency of the audio modulation signal (FMM output signal), so the audio To prevent pulse noise from being superimposed on the signal, the capacitor C2 delays the rise of the differential pulse signal to attenuate high-order harmonic components. When transmitting a digital signal and an analog signal in a superimposed manner on one transmission path, the amplitude of the analog modulation signal must be made smaller than that of the digital modulation signal in order to eliminate transmission errors in the digital signal. In such a case, the harmonic signal of the digital differential pulse is likely to affect the audio signal. If each pulse of the digital modulation signal (FSK signal) is converted into a sine wave and then applied to the transmission line 250, this inconvenience can be eliminated, but doing so will inevitably complicate the circuit configuration. In addition,
Resistor R1 may be omitted.

Output port P of microcomputer CPU1
14 is connected to a buzzer BZ via an inverter, and output ports P15 and P16 are connected to relays RL1 and RL via an inverter, respectively.
2 are connected.

Two output ends of the distributor 190 are connected to tuners TU1 and TU2, which are connected to monitor televisions TV1 and TV2, respectively. Chiyuna
TU1 and TU2 are each modulator 210
and the frequency of the high frequency signal output from 220. The input end of a stabilized power supply circuit that supplies power to tuners TU1 and TU2 and monitor televisions TV1 and TV2 is connected to a power supply line via a contact point of relay RL2.

The contacts of relay RL1 are connected to the input terminal of a stabilized power supply that supplies power to the audio signal circuit and to a 12V power supply line.

Microphones MC1 and MC2 are connected to a differential amplifier DFA composed of an operational amplifier.
A high-pass filter HPF configured using an operational amplifier is connected to the output terminal of the differential amplifier DFA. A low-pass filter LPF configured using an operational amplifier is connected to the output end of the HRF.
The output signal of the low pass filter LPF is sent to the amplifier
It is amplified by the AMP and applied to the input terminal Audio in of the FM modulator FMM via a capacitor. FMM
A predetermined DC bias voltage is applied to the input terminal Audio in of the input terminal Audio in through a variable resistor VR1. variable resistor
VR1 is for setting the center frequency of the FM modulated wave. The FM modulator FMM is configured as a one-chip integrated circuit, and the FM modulation circuit 95 is
It consists of an FMM and electric coils, capacitors, resistors, etc. connected to each terminal. fm modulator
The output end of the FMM is connected via a capacitor to a transmission line leading to the slip ring SA1.

FIGS. 4a and 4b show the electric circuit of the device on the vehicle body side. This will be explained with reference to FIGS. 4a and 4b. Microcomputer CPU2
are connected to FSK modulators 150 and 160 having the same configuration as the modulators 100 and 110 shown in FIG. 3b. The output terminal of the FSK modulator 150 is a driver, a protective resistor R2, a coupling capacitor C3,
The delay capacitor C4 is connected to the output end of the driver, similarly to the steering operation board side.
The input end of the FSK demodulator 160 is connected to a transmission line 250 leading to the slip ring SA2 via an input circuit including a Schmitt trigger ST2 and the like.

The input terminal of the FM demodulation circuit 170 is a slip ring.
It is connected to SA2. The FM demodulation circuit 170 is
It consists of a ceramic filter CFT, an integrated circuit FMD for FM signal demodulation, a low frequency amplifier AM1, etc. The power supply of the FM demodulation circuit 170 is relay RL3.
is supplied through the contacts. FM demodulation circuit 170
The output end of is connected to the contact of relay RL5.
The amplifier AMP connected to speaker SP is
It consists of a CLP, a low frequency amplifier AM2, and a power amplifier PA. The power amplifier PA has an output transformerless OTL configuration. The input end of amplifier AMP is connected to one contact of relay RL2.

Other ports of the microcomputer CPU2 include a branch connection circuit 180, a transistor for controlling a horn drive relay RL6, and a relay RL7.
The inverter that controls the BZ and the inverter that drives the buzzer BZ are connected. A telephone TEL, a mobile device TRX, an FM demodulation circuit 170, and an amplifier AMP are connected to the branch connection circuit 180.
In the telephone TEL block, DI is the dial code output terminal, CP is the 1200 baud clock pulse output terminal, PS is the power on/off control input terminal, CI is the control instruction signal, ("0": call possible, "1": (Unable to make calls)
Input terminal, HK is a hook signal (on-hook/off-hook) output terminal, T is a transmission audio signal output terminal, R is a reception audio signal input terminal, and POW is a power supply terminal. In the mobile device TRX, both HK1 and HK2 are hook signal input terminals. Branch connection circuit 180
relays RL1, RL2, RL3, RL4 and
RL5 is provided, and these are controlled by a microcomputer CPU2.

Two video rams V _RAM1 and V _RAM2 are connected to the microcomputer CPU3. CPU3
outputs address data and inputs/outputs data via ports DB0 to DB7. Address data is latched by a signal from port ALE and applied to the address ports of V _RAM1 and V _RAM2 . When a write instruction signal WT or a read instruction signal RD is received from the CPU 3, V RAM1 and V _RAM2 write to or read from the memory at the specified _address at that timing.
One of V _RAM1 and V _RAM2 is selected depending on the level of the signal from port P21 of CPU3.

As is generally well known, the video rams V _RAM1 and V _RAM2 generate television scanning synchronization signals,
In synchronization with the signal, memory data is sequentially read from different addresses at a predetermined timing and output as an image signal. Therefore, if you change the data in the built-in memory, the state of the output image signal will also change, and by writing predetermined data to a predetermined address in this memory, you can create a television image for displaying predetermined numbers or characters, etc. A signal is generated. The image signal and synchronization signal generated in this manner are applied to modulators 210 and 220, and output as high-frequency modulation signals to transmission line 250 via mixer 230 and the like. The output of V _RAM1 is applied directly to modulator 210, while the output of V _RAM2 is applied to the relay
It is applied to the modulator 220 via the contact of RL8.
The output of V _RAM2 and the output of the rear confirmation television camera TVC are selectively applied to the signal input terminal of the modulator 220 depending on the state of the contact of the relay RL8.

The input port P27 of the CPU3 is connected to a permanent magnet that is connected to the speedometer cable of the vehicle and rotates according to the vehicle speed, or a reed switch SS.
is connected. Ports P10-15 of CPU3
An analog-to-digital converter ADC is connected to the ADC, and the output end of an amplifier AM3 connected to the fuel gauge is connected to the input end of the ADC. Drivers that drive relays RL9 and RL8 are connected to output ports P16 and P17 of CPU3, respectively.

Port P14 of microcomputer CPU2,
P15, P16 and CPU3 ports P22, P2
3. P24 are connected to each other, and through these ports, CPU2 and CPU3 can send commands and commands to each other.
Transmits signals such as data. The microcomputer CPU3 and its peripheral circuits (display circuit system) are powered on and off by the CPU2.

The general operation of the FSK modulation circuit 100 will be explained with reference to FIGS. 3a and 3b. Input end CLOC
A fixed periodic pulse signal (clock pulse) is applied from the output port ALE of the microcomputer CPU1. Counter Z1 divides the frequency of this clock pulse and outputs two types of signals with different periods. When the input terminal SW is at the FSK signal output permission level H, one of the two output signals of the counter Z1 is selected according to the level of the signal applied to the data input terminal DIN, and is output at the period of that signal. end
The levels of DOLC and DOHA change in a binary manner.

This signal causes transistors Q1 and Q
2 is controlled on/off, and when the capacitor is switched on/off, charging and discharging of the capacitor occurs, and positive and negative polarity signals are generated in the transmission path. In other words, since the period of this signal changes depending on the signal level set at the input terminal DIN of the modulator,
If you set the specified serial data in DIN,
An FSK signal corresponding to the data is output to the transmission path. When port P11 is at low level L, low level L and high level H are applied to transistors Q1 and Q2, respectively. In this state, transistors Q1 and Q2 are both turned off and do not output the FSK signal.

When an FSK signal exists on the transmission path, an FSK signal with a predetermined amplitude appears at the output end of the Schmitt trigger ST1. The FSK demodulator 110 demodulates this signal and outputs a binary signal according to the period of the FSK signal to the CPU.
1 to input port T0.

FIG. 5 shows an outline of signal waveforms at each part of the device.
In this example, as shown in FIG. 5, a large number of signals are superimposed on one transmission path. In this example, the frequency of the FSK signal is 50KHz.
and 100 KHz, the center frequency of the FM signal (audio modulation signal) is 10.7 MHz, and the frequencies of the signals output by modulators 210 and 220 are set to different television channel frequencies.

Schmitt triggers ST1 and ST2 are connected between the FSK demodulators 110 and 160 and the transmission line, respectively.
is equipped, which removes signal components other than the FSK signal and noise, so that only the FSK signal extracted from a large number of signals is applied to the FSK demodulator.

The FM demodulation circuit 170 is also equipped with a ceramic filter (bandpass filter) CFT.
This extracts the FM signal (audio modulation signal) component. Furthermore, tuners TU1 and TU2 are each equipped with a tuning circuit that extracts a signal component of a predetermined frequency, and are equipped with modulators 210 and 2, respectively.
Demodulate signal components from 20 and monitor TV
1 and TV2.

A DC voltage for power transmission is applied to the transmission line 250 at the same time as the signal voltage, but since each modulator output end and demodulator input end are connected to the transmission line 250 via a capacitor, this does not cause any inconvenience. do not have.
Furthermore, although the battery and power supply circuits 70 and 120 have low impedance, the electric coils L1 and L2 have high impedance to high frequency signals, and these are the battery and power supply circuits 70 and 120.
120, the impedance of the transmission line 250 seen from each modulation circuit and each demodulation circuit is relatively high.

In this example, capacitors C2 and C4 are connected to the output end of the FSK modulation circuit, so transmission line 2
The FSK signal applied to the transmission line 250 has a relatively smooth rise, but if there is no capacitor C2 or C4, a differential signal with a sharp rise will be applied to the transmission line 250, as shown by the dashed line in FIG.
is applied to the FMD, and a sharp pulse signal appears in the FMD input signal at the timing of the rise of the differential signal.

FIG. 6 shows microcomputers 80 and 13 in the FSK modulation circuits 100 and 150 of the embodiment.
0 shows the bit configuration of the transmitted signal applied. 6th
To explain with reference to the figure, this signal is the first 10
It consists of a bit mark signal (high level: "1"), followed by a 1-bit start bit, 8-bit data, and an 8-bit BCC code.
In the 8-bit data, bits 0 to 4 indicate the type of key, bit 5 indicates key on/off (“1” is on, “0” is off), and bit 6 is
and 7 indicate a group of keys. In this example, the key groups are A, indicated by "00", and "01".
It is divided into three groups: B, shown by 10, and C, shown by 10.

To explain with reference to Figure 2b, key group A includes numeric keys (0 to 9), #, *, and clear keys.
Key group B is the horn key, key group C is the rear check key, fuel key, vehicle speed display key (speed), and call/off key CALL/OFF.

FIG. 7 schematically shows the operation of the device when performing a calling operation on the on-board telephone from the steering operation board, and the operation of the device when performing a receiving operation. This will be explained with reference to FIG.

Making a call Enter the telephone number of the other party using the numeric keys, * and # on the steering wheel operation board. The microcomputer now stores the keyed-in telephone number.

Wait for the call-off key CALL/OFF to be pressed.

When the call-off key CALL/OFF is operated,
Automatically call the recipient of the memorized phone number.

When the called party picks up the receiver (off-hook), hands-free communication becomes possible. Note that if the hold key HOLD is operated here, relay RL5 is activated, and the microphones MC1 and MC2 on the microphone, that is, on the steering wheel, are cut off from the mobile device TRX, and no sound is transmitted from the vehicle.

When the call-off key CALL/OFF is operated again, it is determined that the call is over and the communication is terminated.

Receiving operation When the other party calls the on-board telephone, a ring tone sounds.

Waits for the call-off key CALL/OFF to be operated.

When the call-off key CALL/OFF is operated,
The state is the same as when the receiver is normally lifted, and the other party's voice is output from speaker SP, and microphone MC1 and microphone on the steering control board are output.
MC2 is connected to the on-board telephone as a transmitter.

When the call-off key CALL/OFF is operated again, it is determined that the call has ended and the communication is terminated.

8a and 8b show the operation of the steering operation board shown in FIG. 3a. The operation of each step of the steering operation board will be explained with reference to FIGS. 8a and 8b.

S1 The contents of the memory are set as initial values, and the status of each output port of the microcomputer 80 is set to the initial level. With this process, the output port P
11 becomes low level L, and output of the FSK signal is prohibited.

S2 key reading signal output port ie P20,
Set the data output to P21 and P22 to initial values. This initial data is a value in which the bit corresponding to the output port connected to the row line of the key matrix from which reading is started is set to ``0'' (i.e., low level L), and the other bits are set to ``1'' (i.e., high level H). It is set as. In this embodiment, in the initial setting, the bit corresponding to port P20 is set to "0", and the bit corresponding to port P21 and P2 is set to "0".
The bit corresponding to 2 is set to ``1''.

S3 Outputs predetermined data to ports P20, P21 and P22. This allows port P2
Any port from 0 to P22 is at low level L,
Other ports become high level H.

S4 Read the levels of input ports DB0 to DB7 connected to the column lines of the key matrix. Third
Referring to figure a, input ports DB0 to DB7 are pulled up to the power supply line Vcc via resistors, and each key is connected in a matrix between output ports P20 to P22 and input ports DB0 to DB7. Therefore, for example, when key 0 of key matrix 90 is pressed, at the timing when low level L is set to output port P20, the levels of input ports DB0 to DB7 are L, H, H, H, H, H, respectively. H and H.

S5 Inverts 1/0 of each bit of the data read in step S4. In other words, take the complement.

S6 Compare the key reading data obtained in step S5 with the numerical value 0. If the value is 0, there is no key input, so proceed to step S13; otherwise,
Proceed to step S7.

S7 Save key reading data to specified memory.

S8 To eliminate the influence of mechanical vibrations, that is, chattering, on the key contacts, wait a predetermined time (for example, 10 msec) for the vibrations to subside.

S9 Read the level of ports DB0 to DB7 again.

S10 Calculate the logical OR of each bit of the value read in step 9 and the value saved in the memory in step 7.

S11 Check whether the calculation result in step S10 is not 0. If it is not 0, it is assumed that no key input has been made and the process proceeds to step S13; otherwise, the process proceeds to S12.

S12 Data “0” of key reading line signal data output to output ports P20, P21 and P22
An 8-bit key code corresponding to the pressed key is generated from the data read from ports DB0 to DB7.

S13 The data “0” bit of the key reading line signal data output to output ports P20/P22 is
Shift one bit to the adjacent bit.

S14 Check whether one key reading scan is completed. If not finished, step
Return to processing from S3.

S15 Since there was no key input, the 8-bit code
The key code is 00H (hexadecimal display).

S16 Load the key code from the previous key reading scan from memory.

S17 Calculate the logical OR of each bit between the old key code loaded in step S16 and the new key code exposed in the current key reading scan.

S18 Check whether the calculation result is 0. If the key is 0, that is, there is no key operation, the process returns to step S2; otherwise, the process proceeds to step S19.

S19 Store the newly generated key code in the memory at a predetermined address.

S20 Check whether the key code belongs to key group A.

S21 Checks if key is pressed or released. The keys of group A, ie, the numerical keys, * key, # key, clear key CLR, and hold key HOLD, are valid only when they are pressed, so if the keys are released, the process jumps to step S2.

S22 The buzzer sounds once to confirm key input.

S23 Check whether the pressed key belongs to group B. The keys of group B, ie, the horn keys, are valid both when pressed and when released.

S24 Sends the generated key code data to the transmission line and notifies the device on the vehicle body that a key input has been made. This process will be explained in detail later.

S25 Check whether the data was sent correctly in the data transmission in step S24.

S26 Check whether the pressed key belongs to group C. Regarding keys of Group C, namely rear confirmation key, fuel key, vehicle speed display key, and call-off key CALL/OFF,
Every time a key is pressed, data that inverts the on/off state of the key is transmitted.

S27 Load data indicating the on/off status of group C keys from memory.

S28 From the key code and the data loaded in step S27, a new key code with the on/off state of the group C key reversed is generated. For example, if the call-off key was turned on in the previous key operation, key code data indicating that the call-off key is turned off is generated in the current key operation.

S29 Similar to step S24, S30 checks whether the data was sent correctly in the data transmission of step S29.

S31 Invert the contents of the memory that stores the on/off status of group C keys.

S32 Depending on the state of the group C key, the relays RL1, RL2, buzzer BZ, etc. connected to the output port P15 of the microcomputer 80 are turned on/off.
Performs off control. As a result, the FM modulation circuit 95 and display circuits TV1, TV2, TU1,
TU2 is controlled.

S33 An error occurred in data transmission, so the buzzer
Sounds BZ twice to notify the driver that an error has occurred.

S34 A key reading error occurred, so the buzzer BZ
sounds three times to notify the driver that an error has occurred.

9a, 9b and 9c, 4a
The microcomputer shown in Figures and Figure 4b
The operation of CPU2 (130) is shown. Each operation step will be explained with reference to FIGS. 9a, 9b and 9c.

S51 The contents of the memory are set as initial values, and the status of each output port of the microcomputer CPU2 is set to the initial level. Through this process, the output port P11 becomes a low level L, and output of the FSK signal is prohibited.

S52 Check whether the telephone receiver is off the hook.

S53 The telephone receiver is off the hook, so
Output H to output port HK20 and relay RL
Turn on 4, output H to output port HK10, output L to output port Audio, and relay
Set RL2 and RL3 off. Now you can use the phone in the same way as a normal car phone.
You can use TEL.

S54 Loads the contents of the memory that stores hands-free call instructions from the steering wheel control board.

S55 Check whether hands-free calling is specified. In the initial state, hands-free calling is not specified, so proceed to step S57, but if the call-off key on the steering wheel operation board
When CALL/OFF is set to on (CALL), hands-free calling is specified and step S56
Proceed to.

S56 Output H to output port HK20 and relay
Turn on RL4, set H to output port HK10, output H to output port Audio, and activate the relay.
Turn on RL2 and RL3, output L to output port PS, and set relay RL1 on.
Now, the telephone TEL and the mobile TRX are powered on, the FM demodulation circuit 170 is turned on, and the amplifier is connected to the audio receiving line of the mobile TRX.
AMP is connected.

S57 Output L to output port HOLD and relay
Turn off RL5, output L to output port HK20, turn off relay RL4, and output port HK20.
10 to L, outputs L to the output port Audio to turn off relays RL2 and RL3, and outputs H to the output port PS to set relay RL1 to OFF. Now the phone TEL, mobile device
The power of the TRX and FM demodulation circuit 170 is turned off, and the telephone TEL and mobile device TRX are connected.

S58 Receive data from steering operation board. This will be explained in detail later.

S59 Determines whether data transmission generated by key operations on the steering operation board is received from the steering operation board.

S60 Determine whether the sent data is a group A key code.

S61 Key code determines whether it is a numeric key, * key, or # key.

S62 key code determines whether the hold key is HOLD.

S63 Key code determines whether it is a clear key CLR.

S64 Clears the memory address counter that stores the key codes of the numeric keys sent so far. In other words, the previous numeric key input is canceled.

S65 Determine whether the key code belongs to group B.

S66 Determine whether the key code corresponds to a horn key.

Is the S67 key code a key switch? S68 The horn key has been released, so set the horn to OFF.

S69 The horn key was pressed, so set the horn on.

S70 Check whether the key code is from group C.

S71 Since the key code received as data is not one of groups A, B, or C, it is treated as a data reception error and the buzzer BZ is set to 3.
Ring twice.

S71 Loads the contents of the memory that stores hands-free call instructions from the steering operation board.

S73 Check whether the data loaded on S72 specifies hands-free calling.

S74 Loads the contents of the memory that stores instructions by the HOLD key.

S75 Inverts the 1/0 (on/off) of the data loaded in S74 and stores it in the original memory. Therefore, if there is no previous hold instruction,
A predetermined bit of the data is set to "1", that is, a hold designation.

S76 Check whether hold is specified.

S77 Since hold release is specified, output L to the output port HOLD and set relay RL5 to OFF. The signal output terminal of the FM demodulation circuit 170 is now connected to the transmission audio input terminal T of the mobile device TRX, and it becomes possible to talk using the microphones MC1 and MC2 on the steering wheel.

Since S78 hold was specified, the output port
Output H to HOLD and set relay RL5 to ON. This disconnects the output end of the FM demodulation circuit 170 from the mobile device TRX.

S79 The key code for the numeric key has arrived, so enter that code into the BCD corresponding to the numeric key value.
(Binary Coded Decimal) code and store it in memory at a specified address.

S80 Increments the contents of the counter that specifies the memory address that stores the BCD code of the numeric key.

S81 Checks whether the key code received from the steering operation board indicates operation of the call-off key CALL/OFF. If it is not the call/off key, step S201 is executed.

Determine whether the S82 key code indicates the on (CALL) state of the call-off key.

S83 Since the call-off key has been set to OFF, the contents of the memory that stores the hands-free call designation are set to "0" (hands-free call cancellation).

S84 Since the call-off key has been set to CALL, the contents of the memory that stores the hands-free call designation are set to "1" (hands-free call designation).

S85 Check whether the telephone receiver is disconnected from the telephone.

S86 Output H to output port HK20 and relay
Turn on RL4, set H to output port HK10, output H to output port Audio, turn on relays RL2 and RL3, and set output port PS to H.
Outputs L to turn on relay RL1. Now, the telephone TEL and the mobile TRX are powered on, the FM demodulation circuit 170 is turned on, and the amplifier is connected to the audio receiving line of the mobile TRX.
AMP is connected.

S87 Waits for the relay operating time and the time required for the mobile device to enter the specified operating state after power-on.

S88 Check whether the mobile unit TRX is powered on.

S89 Check whether the vehicle is in a position where it can communicate (whether radio waves can be received). this is
This is determined by checking whether the TRX output terminal CI is at a level that indicates that a call is possible.

S90 Since the vehicle is in a position where a failure has occurred or communication is not possible, the buzzer BZ will sound twice to notify the driver that an error has occurred.

S91 Set the contents of the memory that stores the hands-free call designation to "0" (hands-free call cancellation).

S92 4-bit BCD of numerical value input using numerical keys
The contents of the memory storing the code are read from the address specified by the numerical pointer (address counter) and loaded into a predetermined register.

S93 Transfer the BCD code obtained in step S92 to the phone.
Convert to the same code as the dial code that generates TEL.

S94 In synchronization with the pulse signal output from the PC end of the mobile station TRX, output the dial code obtained in S93 sequentially to the DI end.

S95 Increment the value of the numerical pointer once.

S96 Check whether all BCD codes have been read from memory. This is determined by looking at the value of the numerical pointer. If not finished, step
Return to S92 and read the BCD code from the next numerical pointer.

S201 Check whether a key related to the TV display, ie, a rear confirmation key, a fuel key, or a vehicle speed display key, has been pressed.

S202 Determine whether the current key operation is to set the display on or off.

S203 Executed when setting a predetermined display to off. In addition to the display to be set off this time, it is determined whether any of the rear confirmation display, fuel display, and vehicle speed display is set to on (display).

S204 Since the rear confirmation display, fuel display, and vehicle speed display are all set to OFF, relay RL7 is set to OFF, and microcomputer CPU3
and the power supply to the surrounding display circuits.

S205 Of the display status memory allocated to rear confirmation display, fuel display, and vehicle speed display,
The items set to be hidden this time are set to “0” (hidden)
Set to .

S206 Since display has been instructed, relay RL7 is turned on to supply power to the CPU 3 and its peripheral display circuit.

S207 Wait for a predetermined period of time until the microcomputer CPU 3 becomes ready to receive data, that is, from turning on the power to completing the initial settings.

S208 Using ports P14, P15, and P16, the instruction code corresponding to the display that has been set to on is transmitted to the CPU 3.

S209 Checks whether CPU3 has correctly received the code sent by CPU2 in S208. Specifically, when the code is sent, the CPU 3 outputs a reception completion code (acknowledge signal) after a predetermined time, so the CPU 2 checks the predetermined input port after sending the code, and confirms that the predetermined code from the CPU 3 is received within the predetermined time. monitor to see if it is done.

S210 Of the display status memories allocated to the rear confirmation display, fuel display, and vehicle speed display,
Set the content of what is set to be displayed this time to “1” (displaying).

S211 Since a predetermined acknowledgment signal does not arrive within a predetermined time for the command code sent from the CPU 2, it is assumed that a transmission error has occurred and the buzzer sounds twice.

FIG. 10a shows details of the data transmission (transmission) operation of the microcomputer 80. The operation of each step will be explained with reference to FIG. 10a.

S101 8-bit CRC for transmitted data
Generate check character BCC.

S102 Set a predetermined value to a limit counter that limits the number of data transmissions.

S103 Set output port P11 to H and FSK
The bit data of the mark, start bit, transmission data, and BCC code are sequentially set to the output port P10 in synchronization with the clock.

S104 Set L to output port P11 and FSK
Prohibit signal output.

S105 Check whether there is data input from the other party's FSK modulation circuit. If there is no data input, the process advances to step S107.

S106 Check whether the data sent from the other party is an acknowledgment ACK0 indicating data reception confirmation. As will be explained later, when data is transmitted, the receiving side outputs ACK0 to the transmitting side.

S107 Decrement the limit counter value and
It is determined whether the result is 0 or not. If it is not 0, the process returns to S103, and if it is 0, the process proceeds to S113.

S108 Set H to output port P11 again to enable FSK signal output, mark,
The start bit and each bit of the acknowledge ACK1 indicating confirmation of ACK0 are output continuously in synchronization with the clock.

S109 Set L to output port P11,
Prohibits FSK signal output.

S110 Check whether an FSK signal has arrived from the other party (receiving side). As will be explained later, when the receiving side receives an acknowledgment ACK1 from the transmitting side after outputting an acknowledgment ACK0,
Therefore, the FSK signal is no longer output, but ACK1
If it does not receive it, it will output the FSK signal including ACK0 again. Therefore, from the receiving side here
The arrival of the FSK signal means that data ACK1 from the transmitter has not been received by the receiver.

S111 Since ACK1 has not been received by the receiving side, the value of the limit counter is decremented once and it is checked whether the value is 0 or not. 0
Otherwise, return to step S106 and ACK1 again.
is transmitted, and if it is 0, the process advances to step S113.

S112 Since data transmission is completed within the predetermined number of times set in the limit counter, "OK" is set in the transmission result code.

S113 Even if data is transmitted the predetermined number of times set in the limit counter, data and acknowledgment ACK1 are not transmitted normally.
Set “NG” to the transmission result code.

FIG. 10b shows details of the data receiving operation of the microcomputer 130. The operation of each step will be explained with reference to FIG. 10b.

S121 Check whether the FSK signal has been received, that is, whether data has been input to the input port T0.

S122 Since no data comes to input port T0,
A code corresponding to no data reception is set in the data reception memory.

S123 A predetermined value is set in a limit counter that limits the number of data reception operations for one data transmission.

S124 CRC check character from received data
Generate BCC.

S125 Compare the BCC value of the received data and the BCC value generated in step S124. If the two are equal, it is determined that the data has been received correctly and the process proceeds to step S128; otherwise, the process proceeds to S126.

S126 Since an error has occurred, the limit counter is decremented once and checked to see if the result is 0. If it is not 0, return to S127,
If it is 0, proceed to S134.

S127 Check if there is data input.
If there is received data, proceed to S124, otherwise
Proceed to S126.

S128 Since the data has been received normally, the output port P11 is set to H so that the FSK signal can be output, and the mark, start bit, and acknowledge ACK0 bits are output continuously in synchronization with the clock.

S129 Set L to output port P11,
Prohibits FSK signal output.

S130 Check whether the FSK signal is received on the receiving side.

S131 Check whether the received data is an acknowledgment ACK1 from the transmitting side issued in response to an acknowledgment ACK0 from the receiving side. If ACK1, proceed to S133, otherwise proceed to S132.

S132 Decrement the contents of the limit counter once and check whether the result is 0. If it is not 0, the process returns to S128, and if it is 0, the process proceeds to S134.

S133 Since data transmission is completed within the predetermined number of times set in the limit counter, "OK" is set in the transmission result code.

S134 Even if data is transmitted the predetermined number of times set in the limit counter, data and acknowledgment ACK1 are not transmitted normally.
Set “NG” to the transmission result code.

FIG. 11 shows a schematic operation of the microcomputer CPU3. This will be explained with reference to FIG.

S301 Initialize (clear) the output port level and memory contents.

S302 Monitor the levels of ports P22, P23 and P24 and check whether data is being sent from the CPU2.

Check the data sent from S303 CPU2,
Determine whether the instruction is for rear confirmation display. YES
If so, proceed to S306, and if it is set to on, proceed to S306.
The rear check code is set to "1" in S307, and in the case of off setting, the code is set to "0" in S308.

Check the data sent from S304 CPU2,
Determine whether the instruction is to display the vehicle speed. If YES, proceed to S309, if set to on, proceed to S310
Set the vehicle speed display code to "1" in step S311, and set the code to "0" in step S311 if the setting is off.

Check the data sent from S305 CPU2,
Determine whether the fuel display is an instruction. If YES, proceed to S312; if set to on, proceed to S313
The fuel display code is set to "1" in step S314, and in the case of off setting, the code is set to "0" in step S314.

S315 Check rear confirmation display code. If this code is “1”, proceed to S316,
Set relays RL8 and RL9 on. That is, the power of the television camera TVC is turned on, and the input of the modulator 220 is connected to the output terminal of the TVC.
The image of the rear of the vehicle captured by the television camera TVC is now output in the form of a television image signal, and a high frequency signal modulated by this signal is sent to the transmission line 25.
0 to reach the steering control board.
This signal is demodulated to the original TV signal by tuner TU2 on the operation board, and then sent to monitor TV TV2.
is applied to Rear confirmation code is “0” in S315
If so, proceed to S317 and connect relays RL8 and RL.
Set 9 to off. This turns off the TVC and connects the video ram to the input of modulator 220.
V _RAM2 output is connected.

S318 Check vehicle speed display code. When this code is "1", the vehicle speed is displayed. That is, the process first proceeds to S319, where the level of the input port P27 is monitored for a predetermined period of time, and the number of pulse signals applied during that period is counted. Next, S320 calculates the vehicle speed from the count value, and S321
Write the specified data for vehicle speed display to the V _RAM2 memory. Since the V _{RAM 2} generates a television signal according to the memory contents, the signal containing this vehicle speed display information (numerical value) is applied to the modulator 220 and converted into a high frequency modulation signal, and this signal is transmitted via the transmission line 250. The vehicle speed is received and demodulated by the tuner TU2 on the steering operation board, and the vehicle speed is displayed on the monitor TV2. If the vehicle speed display code is "0" in the process of S318, the process advances to S322 and the memory contents of V _RAM2 are cleared.

S323 Check fuel display code. When this code is "1", a fuel display operation is performed. That is, first proceed to S324, instruct the analog-to-digital converter ADC to convert (signal output to P14), and when the conversion is completed (check P15),
Read conversion data from P10 to P13. Convert the converted data to numerical data, and depending on the result
S325 writes data to the specified memory of video ram V _RAM1 . Like V _RAM2 , V _RAM1 sequentially reads the memory contents, generates a television image signal according to the contents, and applies this to the modulator 210. The high frequency modulation signal output from the modulator 210 passes through the mixer 230 and is transmitted to the transmission line 250.
This signal is received and demodulated by tuner TU1 on the steering operation board and applied to monitor television TV1. If the fuel display code is "0" in S323, the memory of V _RAM1 is cleared and the display of TV1 is turned off.

As described above, according to the present invention, the steering operation board and the on-vehicle control device can be connected using at least one transmission line, so the configuration of the connection mechanism is simple, and moreover, the output terminal of the digital modulator Since the signal delay means is provided, the audio signal from the microphone on the steering operation board can be faithfully transmitted without being affected by the digital signal.

[Brief explanation of drawings]

FIG. 1 is a schematic system block diagram of one embodiment of the present invention. Fig. 2a is a perspective view showing the vicinity of the steering wheel and driver seat of an automobile equipped with the device shown in Fig.
Perspective view showing the steering wheel in Figure 2c.
The figure is a side view showing the mounting structure of the steering wheel part in Figure 2a, Figures 2d and 2e are
They are an enlarged sectional view and an exploded perspective view showing the mounting structure of the brush BA1, slip ring SA1, etc., respectively. FIG. 3a is a block diagram showing an electric circuit provided on the operation board on the steering wheel of the apparatus shown in FIG. 1, and FIG. 3b is a block diagram showing the configuration of an FSK modulation/demodulation circuit. FIGS. 4a and 4b are block diagrams showing electric circuits provided on the vehicle body side of the apparatus shown in FIG. 1. FIG. 5 is a waveform diagram showing schematic signal waveforms of each part of the device shown in FIG. FIG. 6 is a plan view showing the structure of a data string of a signal (FSK) transmitted by the device of FIG. 1. FIG. 7 is a flowchart outlining the outgoing and receiving operations when making a telephone call using the apparatus shown in FIG. 8a and 8b are flowcharts showing the operation of the microcomputer CPU1 in FIG.
Flowchart showing the operation of CPU2, No. 10a
The figure is a flowchart showing the data transmission (sending) operation of microcomputer CPU1 in Fig. 1, Fig. 10b is a flowchart showing the data reception operation of microcomputer CPU2, and Fig. 11 is a flowchart showing the operation of microcomputer CPU3. It is. 1: Driver seat, TEL: Telephone, 3: Steering wheel, 4: Steering operation board, 5: Operation panel, 38, 41: Support, 3
9, 42: Gear, 40: Steering shaft, 43: Connection member, 44: Printed circuit board, 51: Insulator plate, 52, 53: Shield plate, 54: Resin collar, 70, 120: Constant voltage power supply, 80:
Microcomputer, 90: Key switch (switch means), 95: FM modulation circuit (analog modulation means), 100: FSK modulation circuit (digital modulation means), 110: FSK demodulation circuit, 130: Microcomputer (communication control device), 150 :FSK
Modulation circuit, 160: FSK demodulation circuit (digital demodulation means), 170: FM demodulation circuit (analog demodulation means), 180: Branch connection circuit, 210, 2
20: Modulator (second modulation means), TV1, TV
2: CRT display (surface display means), TU1,
TU2: Tuner (first demodulation means), V _RAM1 ,
V _RAM2 : Video RAM (display signal generation means),
TVC: TV camera (display signal generation means), MC
1, MC2: Microphone, SA1, SA2: Slip ring, BA1, BA2: Brush, L1, L
2: Electric coil, TRX: Mobile device (communication means), C
1, C3: Capacitor (AC coupling means), C2,
C4: Capacitor (signal delay means), DFA: Differential amplifier, SP: Speaker.

Claims (1)

[Scope of Claims] 1. At least one acoustic-to-electrical conversion means, an analog modulation means for performing modulation with a signal from the acoustic-to-electrical conversion means, a switch means, and a switch means installed on or near the steering wheel. digital modulation means that modulates with a signal according to the operation and outputs a pulse signal with a frequency different from that of the output of the analog modulation means; a signal delay means connected to the output end of the digital modulation means; and a connection between the output end of the digital modulation means and the transmission line. a steering operation board equipped with an AC coupling means connected between; an analog demodulation means installed in the vehicle body for demodulating the signal modulated by the analog modulation means; a digital demodulation means for demodulating the signal modulated by the digital modulation means; An on-vehicle control device comprising a communication means for emitting electromagnetic waves modulated by an audio signal and a communication control device for controlling the communication means according to an output signal of the digital demodulation means; and an electric connection means consisting of a slip ring and a brush. A steering operation board signal transmission device comprising at least one transmission means for connecting a steering operation board and an on-vehicle control device. 2. The steering operation board signal transmission device according to claim 1, wherein the signal delay means is a capacitor connected between the output end of the digital modulation means and the ground end, and the AC coupling means is a capacitor. 3. The steering operation board signal transmission device according to claim 1, wherein the digital modulation means is an FSK modulator. 4. The steering operation board signal transmission device according to claim 1, wherein the analog modulation means is an FM modulator. 5. The power line of the steering operation board and the power line of the on-vehicle control device are connected to the transmission means through AC blocking electric coils, respectively. The steering operation board signal transmission device according to item 4.