JPH05284055A - Receiver - Google Patents

Abstract

PURPOSE:To easily multicouple a demodulation circuit, to make the receiver compact and to reduce the cost by selecting the IF frequency of inter-car information signals to a specified frequency used for the FM broadcasting receiver. CONSTITUTION:An AM broadcasting signal inputted from a terminal 1 is converted to the IF frequency signal of 455kHz by an RF converter 8, AM demodulated by an AM /FM demodulation circuit 11 and outputted as an AM demodulated signal. An FM broadcasting signal inputted from a terminal 2 is converted to the IF frequency signal of 10.7MHz by an RF converter 9, FM demodulated by an AM/FM demodulation circuit 12 and outputted as an FM broadcasting demodulated signal. The inter-car information signal inputted from a terminal 3 is converted to the IF frequency signal of 10.7MHz by an RF converter 10, inputted to the AM/FM demodulation circuits 11 and 12 respectively, outputted from the demodulation circuit 11 as an FM demodulated GMSK demodulated signal and outputted from the demodulation circuit 12 as the AM demodulated signal of an advancing direction identifying signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving device for receiving information communication signals such as car navigation, FM broadcast signals and AM broadcast signals.

[0002]

2. Description of the Related Art A receiver for receiving an FM broadcast signal and an AM broadcast signal is shown in JP-A-1-95628, and a receiver for receiving a signal of an information communication system is shown in JP-A-3-62749. Has been done. Also, T
A double super type receiving apparatus for receiving a V signal is disclosed in Japanese Patent Laid-Open No. 56-144642.

[0003]

Recently, receiving devices such as an in-vehicle TV receiver and a navigation receiving device capable of transmitting and receiving various kinds of information have been commercialized, and the number of automobiles equipped with these has increased. These receiving devices are individually mounted in automobiles, and the high-frequency signal processing circuit or demodulating circuit such as the tuner and front end of the receiving device is shared to reduce the size and cost of the receiving device. Was not considered.

[0004]

In order to solve the above problems, the road-vehicle information signal is 10.7 MHz by an RF converter.
Of the road-vehicle information signal AM signal and GMSK signal are converted to an FM broadcast signal demodulation circuit or A
The M broadcast signal demodulation circuit can be demodulated, and the demodulation circuit is commonly used for FM reception, AM reception, and information communication signal reception.

[0005]

The FM broadcast signal is converted to an IF frequency of 10.7 MHz by the FM converter RF converter and demodulated by the FM demodulation circuit. Further, the AM broadcast signal is converted to an IF frequency of 455 kHz by the AM converter RF converter and demodulated by the AM demodulation circuit. The road-to-vehicle information signal including the GMSK signal, which is a data signal and a frequency modulation signal, and the AM signal, which is a traveling direction identification signal, is an RF for road-to-vehicle information signal.
The converter converts it to an IF frequency signal of 10.7 MHz, the FM demodulation circuit converts the GMSK signal, and the AM demodulation circuit converts it to A.
Since the M signal is demodulated, the demodulation circuit can be shared.

[0006]

FIG. 1 shows a first embodiment of the present invention.

FIG. 1 is a block diagram of a front end capable of receiving a radio AM broadcast signal, an FM broadcast signal and a road-vehicle distance information signal of 2499.7 MHz.

1 is an AM broadcast signal input terminal, 2 is an FM broadcast signal input terminal, 3 is a road-vehicle information signal input terminal, and 4 is AM.
Broadcast demodulation signal output terminal, 5 is GMSK for road-to-vehicle information signal
Demodulated signal output terminal, 6 is FM broadcast demodulated signal output terminal, 7
Is an AM demodulation signal output terminal for the road-to-vehicle information signal. Reference numeral 8 is an AM broadcast signal RF converter, 9 is an FM broadcast signal RF converter, and 10 is a road-vehicle information signal RF converter. 11 and 12 are AM / FM demodulation circuits. AM broadcast signal input from terminal 1 is RF
An IF frequency signal of 455 kHz is converted by a converter 8, AM demodulated by an AM / FM demodulation circuit 11, and an AM demodulated signal is output from an AM broadcast demodulated signal output terminal 4. The FM broadcast signal input from the terminal 2 is converted into an IF frequency signal of 10.7 MHz by the RF converter 9,
The FM demodulated signal is output from the FM broadcast demodulated signal output terminal 6 after being FM demodulated by the / FM demodulation circuit 12. The road-vehicle information signal input from the terminal 3 is 10.7M by the RF converter 10.
AM / FM demodulation circuit converted to IF frequency signal of Hz
11 and AM / FM demodulation circuit 12 respectively
The / FM demodulation circuit 11 outputs a GMSK demodulation signal which is an FM demodulated data signal, and the AM / FM demodulation circuit 12 outputs an AM demodulation signal which is a traveling direction identification signal.
The road-vehicle information signal RF converter 10 includes a bandpass filter 13, a high-frequency amplifier circuit 14, a mixer circuit 15, an oscillator circuit 16,
It is composed of an IF band pass filter 17, an IF amplifier circuit 18, and a PLL circuit 19. 249 input from terminal 3
Bandpass filter 1 for road-vehicle information signal of 9.7MHz
3, input to the mixer circuit 15 via the high frequency amplifier circuit 14,
The oscillating signal of 2510.4 MHz input from the oscillating circuit 16 is frequency-converted and an IF signal of 10.7 MHz is output. The IF signal is an IF band pass filter 17, IF
AM / FM demodulation circuit 11 and AM /
Input to the FM demodulation circuit 12. The oscillation signal of the oscillation circuit 16 is P
It is controlled by the LL circuit.

As described above, by selecting the IF frequency of the road-to-vehicle information signal to 10.7 MHz used in the FM broadcast signal receiver, the demodulation circuit can be easily shared, and the receiver can be made compact and low in cost. Can be achieved. Further, if an AM / FM demodulation IC that is generally used as an AM / FM demodulation circuit is used, further downsizing and cost reduction can be achieved. This AM / FM demodulation IC has an AM signal input terminal, an FM signal input terminal and an A signal input terminal.
Although it has an M demodulation signal output terminal and an FM demodulation signal output terminal, two AMs are required for road-to-vehicle information signal demodulation because AM demodulation signal and FM demodulation signal cannot be normally operated in parallel. But,
The AM / FM demodulation circuit 11 used for the GMSK signal demodulation of the road-to-vehicle information signal as in the embodiment of FIG. 1 is used for the AM broadcast signal demodulation, and the AM / F used for the AM signal demodulation of the road-to-vehicle information signal.
If the M demodulation circuit 12 is used for FM broadcast signal demodulation, the demodulation output signal switching circuit becomes unnecessary.

A second embodiment of the present invention is shown in FIG.

FIG. 2 also shows a block diagram of a front end capable of receiving an AM broadcast signal, an FM broadcast signal and a road-vehicle distance information signal of 2499.7 MHz, similar to FIG. 1. In FIG. The same symbols are attached to those that do. The difference from FIG. 1 is that the AM / FM demodulation circuit is one demodulation circuit. Reference numeral 21 is an AM / FM demodulation circuit, and 22 to 25 are signal switching circuits. The AM signals of the AM broadcast signal and the road-to-vehicle information signal converted into the IF frequency are input to the AM / FM demodulation circuit 21 via the signal switching circuit 22,
The AM broadcast demodulation signal and the AM demodulation signal of the road-to-vehicle information signal are output from the output terminal 4 or 7 via the signal switching circuit 24. Further, the FM broadcast signal converted into the IF frequency and the GMSK signal of the road-vehicle distance information signal are input to the AM / FM demodulation circuit 21 via the signal switching circuit 23, and the FM broadcast demodulated signal and the GMSK demodulated signal of the road-vehicle distance information signal are input. Is output from the output terminal 5 or 6 via the signal switching circuit 25. A
The M / FM demodulation circuit 21 has a structure capable of simultaneously demodulating AM demodulation and FM demodulation. Since one AM / FM demodulation circuit can perform signal processing, the circuit can be simplified and the receiver can be downsized.

A third embodiment of the present invention is shown in FIG.

FIG. 3 shows an FM broadcast signal and 2499.7.
FIG. 4 is a block diagram of a front end capable of receiving a road-to-vehicle information signal of MHz, and those having the same operations as those in FIGS. 1 and 2 are denoted by the same reference numerals in FIG. The road-vehicle information signal input from the terminal 3 is input to the mixer circuit 15 via the band pass filter 13 and the high frequency amplifier circuit 14, and the frequency is converted by the oscillation signal input from the oscillator circuit 16.
The 0.7 MHz IF signal is output. IF signal is IF
AM / via the band pass filter 17 and IF amplifier circuit 18.
Input to the FM demodulation circuit 21. The AM demodulated signal of the road-to-vehicle information signal is output from the output terminal 7, and the GMSK demodulated signal is output from the output terminal 5 via the signal switching circuit 25. The FM broadcast signal input from the terminal 2 is input to the mixer circuit 29 via the tuning filter 26, the high frequency amplification circuit 27, and the tuning filter 28, and the frequency is converted by the oscillation signal input from the oscillation circuit 30 to obtain the 10.7 MHz IF signal. Is output. The IF signal is input to the AM / FM demodulation circuit 21 via the IF bandpass filter 17 and the IF amplification circuit 18, and the FM broadcast demodulation signal is output from the output terminal 6 via the signal switching circuit 25. The oscillation circuit 16 and the oscillation circuit 30 are controlled by the PLL circuit 30.
Reference numeral 31 is a signal switching circuit. The PLL circuit is commonly used for receiving the road-to-vehicle information signal and the FM broadcast signal to simplify the circuit.

A fourth embodiment of the present invention is shown in FIG.

FIG. 4 is a block diagram of a front end capable of receiving the road-vehicle distance information signal. In FIG. 4, components having the same operations as those in FIGS. 1 and 2 are designated by the same reference numerals. The road-vehicle information signal input from the terminal 3 is converted into an IF frequency signal of 10.7 MHz by the RF converter 10 and then A
The M / FM demodulation circuit 21 is input, the terminal 5 outputs a GMSK demodulation signal, and the terminal 7 outputs an AM demodulation signal.
By setting the IF frequency to 10.7 MHz, components such as an audio IC can be used, so that the size of the receiving device can be easily reduced.

A fifth embodiment of the present invention is shown in FIG.

FIG. 5 shows the FM broadcast signal and 2499.7.
FIG. 7 is a block diagram of a front end capable of receiving a TV signal in addition to the roadside-to-vehicle information signal of MHz, and those having the same operation as in FIGS. 1 and 2 in FIG. In the embodiment of FIG. 5, the double superheterodyne system is adopted in the RF converter section in order to optimize the receiving system. 90M input from TV input terminal 30
The TV signal of Hz to 770 MHz and the FM broadcast signal input from the terminal 2 are input filter circuit 31, wide band amplifier circuit.
2499.7 by the first local oscillation signal input from the first local oscillation circuit 34 to the first mixer circuit 33 via 32.
The frequency is converted to the first intermediate frequency (first IF) of MHz. The first IF signal is input to the second mixer circuit 38 via the signal synthesizing circuit 35, the bandpass filter circuit 36, and the amplifying circuit 37, and the second local oscillation signal input from the second local oscillation circuit 39 causes the second intermediate signal of 57 MHz. The frequency is converted to the frequency (second IF). The second IF signal is input to the demodulation circuit unit 41 via the IF amplification circuit 40, and the video demodulation signal of the TV demodulation signal is output from the TV video signal output terminal 42 and the audio demodulation signal is output from the TV audio signal output terminal 43 to FM broadcast demodulation. The signal is output from the terminal 6. On the other hand, 2499.7M input from terminal 3
The road-to-vehicle information signal of Hz is input to the signal combining circuit 35, and the
The second intermediate frequency (572 MHz) is input to the second mixer circuit 38 via the bandpass filter circuit 36 and the amplifier circuit 37 in the same manner as when the signal is received, and the local oscillation signal input from the second local oscillation circuit 39 causes the second intermediate frequency of 57 MHz (second IF). Is frequency-converted into the demodulation circuit section 41 via the IF amplifier circuit 40, the terminal 5 outputs the GMSK demodulated signal, and the terminal 7 outputs the AM demodulated signal. In this way, if the first IF frequency is set to the information signal frequency in the double super system receiving circuit, the circuit after the band pass filter circuit 36 can be shared. Reference numeral 43 is a third mixer circuit, and when a TV signal is received, the difference signal between the two local oscillation signals input from the first local oscillation circuit 34 and the second local oscillation circuit 39 is the PLL tuning circuit.
This is a system in which the first local oscillation circuit 34 is input to 43 and the first local oscillation circuit 34 is controlled, and the second local oscillation circuit 39 is controlled when an information signal is received.

FIG. 6 shows an embodiment of the RF converter for road-to-vehicle information signals of the present invention.

In FIG. 6 as well, elements having the same functions as those in FIG. 1 are designated by the same reference numerals. 50 and 51 are low-pass filters, 52 is a multiplication circuit, 53 is an oscillation circuit, 54 is a PLL circuit, and 55
Is an IF frequency output terminal. Although the present invention shows the case where a multiplied oscillation signal is used as the oscillation signal,
Not only is a low-pass filter provided between the multiplier circuit 52 and the mixer circuit 15 for attenuating signals other than the signals necessary for frequency conversion in the mixer circuit with the oscillation signal and the multiplied signal of the oscillation signal, the high-frequency amplifier circuit 14 and the mixer circuit. It is also provided between 15. By providing the low-pass filter 50, the oscillation signal and the multiplied signal of the oscillation signal can be prevented from leaking from the input of the mixer circuit 15, and the deterioration of the noise figure characteristic can be improved.

[0020]

According to the present invention, the road-to-vehicle information signal is transmitted by RF.
The converter converts it to an IF frequency signal of 10.7 MHz, and the AM and GMSK signals of the road-to-vehicle information signal are F
Since the demodulation circuit can be demodulated by the M broadcast signal demodulation circuit or the AM broadcast signal demodulation circuit and the demodulation circuit can be commonly used for FM reception, AM reception, and information communication signal reception, the size and cost of the reception circuit can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a front end showing a first embodiment of the present invention.

FIG. 2 is a block diagram of a front end showing a second embodiment of the present invention.

FIG. 3 is a block diagram of a front end showing a third embodiment of the present invention.

FIG. 4 is a block diagram of a front end showing a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a front end showing a fifth embodiment of the present invention.

FIG. 6 is a block diagram of an RF converter of the present invention.

[Explanation of symbols]

 1 ... AM broadcast signal input terminal, 2 ... M broadcast signal input terminal, 3 ... Road-vehicle information signal input terminal, 4 ... AM broadcast demodulated signal output terminal, 5 ... Road-vehicle information signal GMSK demodulated signal output terminal, 6 ... FM Broadcast demodulation signal output terminal, 7 ... AM demodulation signal output terminal for road-to-vehicle information signal, 8 ... AM broadcast signal RF converter, 9 ... FM broadcast signal RF converter, 10 ... Road-vehicle information signal RF converter, 11, 12 , 21 ... AM / FM demodulation circuit.

Claims (5)

[Claims] 1. A receiving device capable of receiving an FM broadcast signal, an AM broadcast signal and a road-to-vehicle information signal, wherein a demodulation circuit for the FM broadcast signal or AM broadcast signal and a demodulation circuit for the road-to-vehicle information signal are shared. Receiver. 2. The demodulation circuit according to claim 1, which is capable of FM demodulation and AM demodulation, has a first FM / AM signal input terminal, an AM signal input terminal, an FM demodulation signal input terminal and an AM demodulation signal input terminal. AM signal demodulation circuit and second F
The M / AM signal demodulation circuit, the AM broadcast demodulation signal is output from the AM signal input terminal of the first FM / AM signal demodulation circuit, and the FM broadcast demodulation signal is the FM signal input of the second FM / AM signal demodulation circuit. The data demodulation signal of the road-to-vehicle information signal output from the terminal is the F of the first FM / AM signal demodulation circuit.
A receiving device, wherein the M signal input terminal outputs AM of a road-vehicle distance information signal to an AM signal input terminal of a second FM / AM signal demodulation circuit. 3. A receiver according to claim 1, wherein the demodulation circuit comprises an FM / AM signal demodulation circuit capable of simultaneously demodulating an FM signal and an AM signal. 4. The received road-to-vehicle information signal is converted to an intermediate frequency near 10.7 MHz by an RF converter, and FM / A
A receiving device for demodulating by an M signal demodulating circuit, wherein the intermediate frequency is selected to be a frequency in the vicinity of 10.7 MHz. 5. An RF converter comprises a high-frequency amplifier circuit, a mixer circuit, an oscillator circuit, and a multiplier circuit of an oscillation signal, and a filter circuit for attenuating an unnecessary signal of the oscillation signal and the multiplier signal is provided between the high-frequency amplifier circuit and the mixer circuit. A receiving device characterized by the above.