JPH0238525Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a calling device that can be used in wired or wireless communication equipment.

(Prior art) Conventional squelches in communication equipment detect changes in the noise level obtained when radio waves are received and open/close low frequency amplifiers, or something similar.On the other hand, tone squelch A tone signal is mixed into the voice, the tone signal component is detected, and the low frequency amplifier is opened and closed.

With the former, it is not possible to select a specific partner station for reception, so in order to communicate with the partner station at any time, the reception must be maintained at all times, which may result in unintended communications being heard. This is extremely inconvenient in practice.

The latter requires special parts, tends to have complicated circuits, increases manufacturing costs, and is difficult to use in low-cost equipment.

(Problems to be Solved by the Invention) The objective of this invention is to provide a simple calling device that eliminates the drawbacks of the conventional technology and achieves the functions of sending and receiving calling signals and notifying them with a simple circuit configuration and low cost. .

(Means for Solving the Problem) The gist of the present invention that solves the problem is to alternately operate the receiving circuit 10 and the transmitting circuit 11 by manually opening and closing the transmitting switch _S2 to switch between transmitting and receiving.
In addition, in communication equipment that communicates by switching between a call state and a standby state with a manual switch _S1 , the low frequency signal of the output of the demodulation circuit E of the receiving circuit 10 is inputted, and a rectangular wave having the same wave number as the low frequency of the calling signal is input. A PLL ICQ ₁ is provided which outputs a lock signal if the low frequency signal input from the demodulation circuit E includes a low frequency call signal, and the PLL ICQ ₁ outputs a low frequency square wave. A low-pass filter is installed to shape the waveform into a sine wave.
A connection path is provided for inputting the sine wave output signal of the low pass filter to the modulation circuit F of the transmitting circuit 11, and a connection path is provided for inputting the sine wave output signal of the low pass filter to the audio output circuit consisting of the low frequency amplifier AM and the speaker. A switching circuit is provided that is closed by the lock signal of ICQ ₁ and transmission switch S ₂ , and when transmission switch S ₂ and manual switch S ₁ are placed in reception standby mode, the switching circuit is closed by the lock signal output from ICQ ₁ . When the low-pass filter output low frequency is input to the audio output circuit to generate a notification sound, and the transmission switch S ₂ and manual switch S ₁ are set to the transmission call mode,
The low-frequency output of the low-pass filter is sent to the modulation circuit F of the transmitting circuit 11 via the connection path to transmit a calling signal, and the transmitting switch _S1 closes the switching circuit and outputs the low-frequency output of the low-pass filter as an audio output. A simple calling device is characterized in that it is input to a circuit and output as a notification sound.

(Function) This invention was achieved by taking advantage of the characteristics of the PLL IC and adding a simple peripheral circuit to it. The PLL ICQ ₁ outputs a square wave having the same frequency as the calling signal and a lock signal that is generated when the calling signal is present in the low frequency of the demodulation circuit E input to the PLL ICQ ₁ . The square wave is then shaped into a sine wave by a low pass filter. This sine wave is generated when transmitting switch _S2 and manual switch _S1 are in the reception standby mode, when a ring tone is received (that is, when a lock signal is generated), and when transmitting switch _S2 and manual switch _S1 are in the reception standby mode. When in the transmission call mode, it is input to the audio output circuit and output as a notification sound,
This allows you to confirm that you are receiving a call and that the call is in progress. In the transmission call mode, the sine wave is input to the modulation circuit F of the transmission circuit 11 via the connection path, and is transmitted as a radio wave.

Furthermore, when the transmitting switch _S2 and the manual switch _S1 are in the receiving call mode and the transmitting call mode, the original circuits of the transmitting circuit 11 and the receiving circuit 10 operate alternately to receive and transmit audio. can be done.

(Example) An example of the present invention will be described below based on the drawings. First, NE567 (trade name), which is ICQ ₁ for PLL, or its equivalent product will be used. The power supply to this device is provided via the right hand side of the manual switch _S1 . The selected signal from demodulation circuit E is resistor
R ₁ , added to ICQ ₁ by capacitor C ₁ . Resistor R ₁ is for providing an appropriate signal level to ICQ ₁ , and capacitor C ₁ is for direct current blocking. On the other hand, inside ICQ ₁ , variable resistor VR ₁
The square wave oscillates at the same free-running frequency as the ringing signal frequency determined by the time constant of capacitor _C4 . This square wave output appears at point A and is connected to resistors R ₇ , R ₈ , R ₉ , capacitor C ₈ ,
A high input resistance type low pass filter consisting of _C9 and transistor _Q2 shapes the waveform into a waveform close to a sine wave, and the output is obtained at point D.
One side of this output is led to the modulation circuit F of the transmitting circuit 11 via a connection path consisting of a capacitor C ₇ and a variable resistor VR ₃ , which serves as a calling signal when transmitting a call, and is connected to a variable resistor VR 3. VR ₃ has a capacitor C ₇ for its level adjustment
is for direct current blocking. The other side is a resistor R ₆ , a diode D ₃ , and a diode D 3 , which constitute a switching circuit.
and is led to the output terminal 5 via the resistor R ₁₁ and the capacitor C ₁₁ , and as soon as the cathode potential of the diode D ₃ becomes lower than the anode potential, the D
A pseudo sine wave of points appears as a notification sound. Here, the switching output at point B is the resistance
The cathode potential of diode D ₃ is applied via R ₄ and R ₅ . Capacitor C ₅ is used to smooth the rise and fall of this switching output, making the notification sound audibly smooth, and capacitor C ₆ is used to remove uneasy high-frequency components from the notification sound. Point C is connected to transmitting switch _S2 via diode _D2 and variable resistor _VR2 , and when transmitting switch _S2 is closed, that is, in the transmitting state, the potential at point C is lowered and an alarm sound is emitted. to the low frequency amplifier AM. The variable resistor VR ₂ is used to determine the loudness of the notification sound at that time. Light emitting diode D ₁ resistor from power supply
It is connected to point B via R ₂ , and lights up when ICQ ₁ receives the desired call signal and enters the locked state, indicating that it is receiving a call along with the aforementioned notification sound.

In other words, the arrival of the desired call signal can be detected by both sound and light. The resistor _R3 is used to pull up the potential at point B when _ICQ1 is in an unlocked state. Resistor R ₁₀ is a variable resistor
This is to emit a certain amount of notification sound even when VR ₄ is at the lowest volume position, improving the reliability of information transmission between communication stations.

To use this circuit, first set the frequency of the calling signal using variable resistor VR ₁ and capacitor C ₄ . When making this setting, select the frequency so that there will be no malfunction due to audio signals. If the manual switch _S1 is now set to the W side (standby state), power is applied to this device by the right side of the manual switch _S1 , and the device enters the standby operation. On the other hand, the signal from the demodulation circuit E is not transmitted to the low frequency amplifier AM because the left side of the manual switch _S1 is open. If the signal from demodulator E has a frequency outside the lock range of ICQ ₁ or does not reach the operating level of ICQ ₁ , the potential at point B is approximately the power supply voltage, and diode D ₃ is cut off, and no output appears at output terminal 5. However, when the desired call signal arrives, ICQ ₁ becomes locked, and diode D ₃ becomes conductive to generate a notification sound to notify the arrival of the desired call signal. Then, switch the manual switch _S1 to the T side (talking state) and start a normal call. When the call is over, switch the manual switch _S1 to the W side again to enter the standby state. On the other hand, when calling the other party's station, it is sufficient to close the transmitting switch _S2 while leaving the manual switch _S1 in the standby state, and at this time, the calling signal previously injected from the terminal 6 is emitted from the transmitter. In addition,
When the manual switch S ₁ is on the T side (talking state), power is not supplied by the switch on the right side of the manual switch S ₁ , so even if the transmission switch S ₂ is closed and the transmission state is set, a call signal is not emitted from the transmission circuit 11. It will never happen. In the figure, 7 is an input terminal of the low frequency amplifier AM, 8 is a power supply terminal of the low frequency amplifier AM, 9 is a power supply, 10 is a receiving circuit, 11 is a transmitting circuit, L is a transmission/reception switching relay, 1 to 4 are terminals, _D4 ,
D ₅ and D ₆ are diodes, and C ₂ , C ₃ , C ₁₀ and C ₁₂ are capacitors.

Furthermore, the operation of this embodiment will be explained in detail by dividing it into the following four modes.

(a) Reception standby mode (b) Reception call mode (c) Outbound call mode (d) Outbound call mode The operation of each mode will be explained below along with actual operating procedures.

(a) Reception standby mode (S ₁ : W side, S ₂ : open, L contact: position as shown in the figure) AM (low frequency amplifier) is supplied with power by diode _D5 and diode _D6 and enters the operating state. However, the input signal appearing at terminal 1 (output of E) is AM because the left side of manual switch S ₁ is open.
does not reach. On the other hand, the square wave output in Figure 2 generated at point A is generated by resistors R ₇ , R ₈ , R ₉ and transistors.
A sine wave voltage shown in FIG. 5 is created at point D by a low pass filter consisting of Q ₂ , capacitors C ₈ and C ₉ . Although the sinusoidal voltage constantly generated at point D is guided to terminal 5 via resistor R ₆ , diode D ₃ , capacitor C ₁₁ , and resistor R ₁₁ that constitute the switching circuit, ICQ ₁ In the non-lock state (when there is no low frequency call signal input to terminal 1), the voltage at point B is at a high level (=
Since VCC, diode _D3 in the switching circuit
is cut off and the notification sound (sine wave) is output to terminal 5.
is not output, but when an input signal that locks ICQ ¹ appears at terminal 1 (that is, when a call signal is received), the potential at point B drops to almost OV (a lock signal is generated), so the potential at point D The sinusoidal voltage reaches terminal 5 via resistor R ₆ , diode D ₃ , resistor R ₁₁ , and capacitor C ₁₁ to generate a notification sound. In this way, the circuit portion of resistors R ₄ , R ₅ , R ₆ , capacitors C ₅ , C ₆ and diode D ₃ forms a switching circuit that sends out a notification sound when a call signal is received.

(b) Receiving call mode (S ₁ : T side, S ₂ : Open, L contact: position as shown in the figure) The receiver who hears the notification sound immediately switches the manual switch.
_S1 must be switched to the T side.

As a result, the input signal appearing at terminal 1 can be guided to AM via the left side of S ₁ , VR ₄ , R ₁₀ , C ₁₀ , and terminal 5, and can be heard. At this point, the input signal at terminal 1 must no longer be a ringing signal but an actual voice;
ICQ ₁ is not locked and the notification sound does not leak to terminal 5. If you can hear the notification sound,
This means that the other party is still sending a call signal.

(C) Transmission call mode (S ₁ : W side, S ₂ : closed, L contact: moved to the lower side) Transmission switch S ₂ is a PTT/SW, and when it is closed, the transmission circuit 11 is activated and enters the transmission state. .

On the other hand, since terminal 2 becomes O potential due to S ₂ closing, C
The potential at the point decreases (see Figure 4, VR ₂ determines the level of this decrease). Then, as in case A, the sine wave voltage at point D reaches terminal 5 via R ₆ , D ₃ , R ₁₁ , and C ₁₁ to notify that a ringing tone is being transmitted.

The calling signal itself is sent to the modulator F of the transmitting circuit 11 via C ₇ , VR ₃ , and 6. In this case, AM power is required even in the transmitting state, but this is supplied via the power supply 9 and the right side _D5 of the manual switch _S1 .

(d) Outgoing call mode (S ₁ : T side, S ₂ : closed, L contact: moved to the bottom) This operation is a normal sending state, and no calling signal is sent, so ICQ _1. Power is not supplied to transistor _Q2 and AM. As with normal transmission, close transmitter switch _S2 and connect transmitter circuit 1.
1 only needs to be operated, and this circuit does not operate at all.

Typical examples of call cycles have been described above. The unique feature of this invention is that the calling signal and notification sound are generated by shaping the square wave output of the PLL/IC, and can be realized with a small number of parts.

(Effects of the invention) As described above, according to the invention, a square wave signal of the same frequency as the calling signal outputted by the PLL IC, a lock signal generated when there is a calling signal in the low frequency input signal, and a PLL Using a sine wave signal generated by shaping the square wave output by the IC, the sine wave signal is output as a notification sound in reception mode, and as a call signal and self-indication sound in transmission mode. used.

Therefore, there is no need for separate generation circuits for transmitting and receiving generation circuits for call signals, and PLL ICs and
In addition to a low-pass filter, the calling signal can be sent and received using simple attached circuits such as a switching circuit that uses a sine wave using a lock signal, making it possible to reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the embodiment, Fig. 2 is an explanatory diagram showing the voltage waveform at point A, Fig. 3 is an explanatory diagram showing the voltage waveform at point B, and Fig. 4 is an explanatory diagram showing the voltage waveform at point C. The explanatory diagram, FIG. 5, is an explanatory diagram showing the voltage waveform at point D. S ₁ : Manual switch, S ₂ : Sending switch, 10:
Receiving circuit, 11: Transmitting circuit, E: Demodulating circuit, F:
Modulation circuit, Q ₁ : PLL IC, {1, 2, 5, A,
B, C, D}: Terminal.

Claims (1)

[Scope of claim for utility model registration] The receiving circuit 10 and the transmitting circuit 11 are connected to a transmitting switch.
S ₂ can be operated alternately by manual opening and closing operation to switch between transmitting and receiving, and can also be manually switched between talking state and standby state.
In a communication device that communicates by switching with _S1 , the low frequency signal of the output of the demodulation circuit E of the receiving circuit 10 is inputted, and a square wave having the same frequency as the low frequency of the calling signal is output, and from the demodulation circuit E. A PLL ICQ ₁ is provided that outputs a lock signal if the input low frequency signal includes a low frequency call signal, and a low pass filter is provided that shapes the low frequency square wave output from the PLL ICQ ₁ into a sine wave. A connection path is provided for inputting the sine wave output signal of the low pass filter to the modulation circuit F of the transmitting circuit 11, and a connection path is provided for inputting the sine wave output signal of the low pass filter to the audio output circuit consisting of the low frequency amplifier AM and the speaker. A switching circuit is provided in the middle that is closed by the lock signal of ICQ ₁ and transmitting switch _S2 , and when transmitting switch _S2 and manual switch _S1 are placed in reception standby mode, the switching circuit is closed by the lock signal output by ICQ ₁ . closes and inputs the low-frequency output of the low-pass filter to the audio output circuit to generate a notification sound.Also, when the transmission switch _S2 and manual switch _S1 are set to the transmission call mode, the low-pass filter output low The frequency is transmitted to the transmission circuit 1 via the connection path.
At the same time, transmitting switch _S1 closes the switching circuit and inputs the low frequency output of the low-pass filter to the audio output circuit to output it as a notification sound. A simple calling device featuring: