JPS6320209Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in the calling circuit configuration of an intercom device with a television monitor function.

FIG. 1 shows an example of a paging circuit configuration of a conventional intercom device with a television monitor function.

When the ring switch S is turned on in the handset 1, the ring tone oscillator 3 is activated for a certain period of time by the timer (monostable multi) 2, and the high frequency oscillator 4 is activated.
The carrier wave (frequency c) that is constantly transmitted from
The signal is modulated by the ringing tone oscillation frequency t, amplified by the high frequency amplifier 5, and sent to the main unit 8 via the bandpass amplifier 6 via the line cable 7. t
The carrier wave modulated by is amplified by a high frequency amplifier 10 via a band waver 9 of the base unit 8, and a calling tone signal t is detected by a demodulator 11 and a ring tone signal band waver 12. Then, the output voltage amplified by the rectifier circuit 13 and the DC amplifier 14 is used to operate the ring tone generating circuit 15, and the speaker 17
The phone was ringing.

By the way, as mentioned above, in the conventional embodiment, the calling tone oscillator 3 is required in the handset 1, and the calling tone signal bandpass filter 12 and rectifier circuit 13 are required in the base unit 8, respectively, and the frequency variation is small. It is necessary to set the ringing tone oscillation frequency t outside the call signal band so as not to interfere with the call, and as a result, the device has a large number of parts and is expensive.

The present invention was made to solve the above-mentioned problems.In an intercom device with a TV monitor function that calls from a slave unit to a base unit, the slave unit transmits a high-frequency signal that constantly sends a carrier wave to the base unit via a high-frequency amplifier. and a timer (monostable multi) that stops the output of the high frequency amplifier for a certain period of time regardless of how the ring switch is pressed when the ring switch is turned on, and the base unit includes a controller unit that oscillates a ring tone signal when the carrier wave is stopped; The purpose of the present invention is to provide an inexpensive and reliable intercom device with a television monitor function by simplifying the circuit and reducing the number of parts by including a loudspeaker amplifier that makes a speaker sound under the control of the controller section.

An embodiment of the present invention will be described in detail below based on the drawings.

FIG. 2 shows the configuration of the calling circuit of the intercom device with television monitor function of the present invention. Handset 20
, a high frequency oscillator 24 connected to a band wave generator 26 via a high frequency amplifier 25 and a modulator 23, a microphone 21 connected to the modulator 23 via a microphone amplifier 22, and a timer (monostable multi) 27.
A call switch S connected to the amplifier 25 via
a demodulator 30 connected to the bandpass amplifier 28 via a high frequency amplifier 29; a speaker 33 connected to the demodulator 30 via a loudspeaker amplifier 31; 31 and a squelch circuit 32 that controls a timer (monostable multi) 27. Base unit 3 connected to slave unit 20 via track cable 49
4 includes a bandpass amplifier 35 connected to the controller section 37 via a high frequency amplifier 36, a loudspeaker amplifier 38 connected to the controller section 37, a speaker 39 connected to the loudspeaker amplifier 38, and a demodulator 40.
a receiver 42 connected to the output of the high frequency amplifier 36 via the receiver amplifier 41; a high frequency oscillator 47 connected to the bandpass generator 43 via the high frequency amplifier 46 and the modulator 44; and a microphone amplifier 45.
The microphone 48 is connected to the modulator 44 via a microphone.

Next, the operation of the intercom device with television monitor function of the present invention having the circuit configuration as described above will be explained.

FIG. 3a shows a specific configuration of the timer (monostable multi) 27, high frequency amplifier 25, and squelch circuit 32 in FIG.
1. It is composed of elements 52 and 53 that determine the time constant. The high frequency amplifier 25 is an inverter logic circuit 54
Its input is a diode 55 and a resistor 56.
It is connected to the output of the NAND circuit 50 via. The squelch circuit 32 includes an amplifier 57 and a rectifier circuit 5.
8. It consists of a switching transistor 59, and the collector of the switching transistor 59 is connected to the NAND circuit 51 via a diode 60. FIG. 3b shows the controller section 37 in FIG. 2, which is composed of a transistor 65, a capacitor 66, a resistor 68, and an IC 67.

When the calling switch S is turned on in the handset 20, a calling trigger signal is inputted from the input terminal 61 of the timer (monostable multi) 27 shown in FIG. 3a. The paging trigger signal is input to a NAND logic circuit 50. Then, it becomes an output signal according to a time constant determined by the resistor 53 and capacitor 52, and is inputted to the inverter logic circuit 54 via the resistor 56 and diode 55. As a result, the carrier wave from the oscillator 24 (FIG. 2) inputted from the input terminal 62 is stopped by the logic circuit 54 for a certain period of time.
In the normal state when no calling operation is being performed, the carrier wave signal is transmitted to the base unit 34 via the line cable 49 shown in FIG.
The signal is inputted to the controller section 37 via the band wave generator 35 and the high frequency amplifier 36. Since the carrier wave signal input from the input terminal 69 (FIG. 3b) of the controller section 37 is amplified by the transistor 65, the IC 67 does not operate. When the carrier wave signal stops for a certain period of time, the output signal of the transistor disappears, and this is detected by the carrier wave detection circuit in the IC 67, and the ring activation is started. The IC 67 outputs the ring signal from the output terminal 70 and the control signal from the output terminal 71. , the control signal causes the loudspeaker amplifier 38 to operate and the speaker 39 to sound. Also, the squelch circuit 32
When making a call from the base unit to the slave unit, the carrier wave signal input from the input terminal 64 is amplified and rectified to turn on the switching transistor 59 and control the loudspeaker amplifier 31 of the slave unit. , its output is set to timer (monostable multi) 27.
This is to prevent the timer (monostable multi) 27 from operating even if the signal is input to the NAND circuit 51 and the call switch S is turned on. As a result, even if the call switch S is turned on during a call, the carrier wave does not stop and there is no problem with the call.

In addition, as another application example, the controller section 37,
It is also possible to switch the loudspeaker amplifier 38 and speaker 39 to, for example, a call indicator light, a motor drive, etc.

As is clear from the above embodiments, in the intercom device with a TV monitoring function that calls from a slave unit to a base unit according to the present invention, the slave unit transmits a high-frequency carrier wave that constantly sends a carrier wave to the base unit via a high-frequency amplifier. The base unit is equipped with an oscillator, a call switch, and a timer (monostable multi) that operates in response to the operation of the call switch and temporarily stops the output of the high frequency amplifier during operation, and the base unit temporarily stops the carrier wave. Since it is equipped with a controller section that detects and oscillates a ringing tone signal, and a loudspeaker amplifier that makes a speaker sound under the control of the controller section, the circuit is simplified, the number of parts is reduced, and the system is inexpensive and reliable. An intercom device with a TV monitor function can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional intercom device with a television monitor function, and FIG. 2 is a block diagram of an intercom device with a television monitor function according to the present invention. Figure 3a is the monostable multi in Figure 2,
A detailed circuit diagram of the high frequency amplifier and the squelch circuit, FIG. 3b is a diagram showing the controller section in FIG. 2. 20...Slave unit, 25...High frequency amplifier, 24...
... High frequency oscillator, 27 ... Timer (monostable multi), 34 ... Base unit, 37 ... Controller section,
38... Loudspeaker amplifier, 39... Speaker, S...
...Switch.

Claims (1)

[Scope of utility model registration request] In an intercom device with a TV monitor function that calls from a slave unit to a base unit, the slave unit includes a high-frequency oscillator that constantly sends a carrier wave to the base unit via a high-frequency amplifier, a call switch, and a call switch that responds to the operation of the call switch. a timer that operates to temporarily stop the output of the high frequency amplifier during operation, and a controller unit that detects the temporary stop of the carrier wave and oscillates a ringing tone signal;
An intercom device with a television monitor function, comprising a loudspeaker amplifier that makes a speaker sound under the control of the controller section.