JPS61121543A - Radio telephone set - Google Patents

Abstract

PURPOSE:To hold a telephone circuit only with the transmission of a pilot signal in a short time when a slave device is started by providing an FF which works on the detection outputs of the reception and pilot signals to a master device together with a relay which holds a gate circuit and a telephone circuit. CONSTITUTION:When a slave device is set under a calling state, a PL (pilot) signal generator 5 produces the PL signals for several seconds and modulates the carrier wave to transmit it to the master device. At the side of the master device, the carrier wave detected by a reception circuit 9 is applied to a signal detecting circuit 17. The circuit 17 produces the 1st control signal, and a diode 23 is turned on via an inverter IV22. Then the electric charge of a capacitor C24 is discharged and an FF 19 is reset. At the same time, the 2nd control signal of an L level is produced from a PL detecting circuit 18 via an LPF 10. Then a capacitor C26 is discharged, and the FF 19 is set to apply the signal supplied from a terminal Q to an NAND circuit 20. When the PL signals are discontinued, the 2nd control signal is changed to an H level. Then a relay 15 is actuated via the circuit 20 and an inverter IV21 for holding a telephone circuit. In a ring-off mode the relay 15 is cut off with cut-off of the carrier wave and the holding state of the telephone circuit is released.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a radio telephone that is capable of maintaining a telephone line without a pilot signal after being activated by a pilot signal.

(→ Conventional technology) In a wireless telephone that has a base unit connected to a telephone line and a handset that allows you to make wireless phone calls via the base unit, there is a conventional method for activating the base unit from the handset. Jitsugan Showa 58-
A pilot signal is used as described in No. 96500. That is, when making a call or in response to a calling signal, when the handset is lifted and put into a talking state, the handset oscillates a pilot signal. The pilot signal is FM-modulated in the transmitting circuit and transmitted from the antenna to the base unit. After receiving the signal with the antenna, the base unit demodulates the pilot signal by amplification, frequency modulation, detection, etc.The pilot signal sets a flip-flop, operates a relay, and closes the telephone line, making it possible to make a telephone call. There is.

rt Problems to be Solved by the Invention The pilot signal is always transmitted from the handset not only at startup but also during a call to confirm that a call is being made, so the carrier wave is always transmitted even in the pilot signal. Modulated. Therefore, the modulation degree for modulating the carrier wave with the audio signal cannot be increased;
The revised FCC standard for 1PK may severely limit the bandwidth. In addition, in the pilot system, when the pilot signal is interrupted, the telephone line is opened.5 The purpose of the present invention is to eliminate the above-mentioned drawback by transmitting the pilot signal only at the time of startup to close the telephone line. The present invention provides a wireless telephone set with the following features.

B) Means for Solving the Problems The present invention provides a signal detection method for detecting a received signal on one device in a device having a base unit connected to a telephone line and a slave unit capable of communicating with the base unit wirelessly. with the circuit.

and a pilot detection circuit that detects the viroft signal.

A 7-lip-flop whose reset terminal is supplied with the signal from the signal detection circuit and the signal from the pilot detection circuit, and whose input terminal is supplied with a clock pulse generated by the signal from the pilot detection circuit, and the output signal of the flip-flop and the pilot. This invention relates to a radio telephone comprising a gate circuit that gates a signal from a detection circuit, and a relay that is operated by the output signal from the gate circuit to close a telephone line.

(E) Function The radio telephone of the present invention has the above-described configuration, and when the handset is placed in a talking state, a pilot signal is generated for several seconds and the carrier wave is FM-modulated. The FM modulated carrier wave is transmitted and received by the base unit, which generates a signal from the signal detection circuit to set the reset terminal of the flip-flop to the OV level and enable it to operate. At the same time, a signal is generated from the pilot detection circuit and a clock pulse is applied to the input terminal of the 71J flip-flop, setting the flip-flop and producing an output signal at the output terminal. The output signal and a signal obtained by inverting the signal from the pilot detection circuit are gated by a gate circuit, and the passed signal operates a relay to close the telephone line. Even after the pilot signal disappears, the flip-flop continues to be set as long as there is a carrier wave, but if one call ends and the carrier wave is no longer transmitted from the handset for a while, or the pilot signal generated at the end of the call causes the flip-flop to be set. Reset the flip-flop, disable the relay, and open the telephone line.

(F) Embodiment An embodiment of the operation of the wireless telephone of the present invention will be described with reference to the drawings. As shown in FIG. an amplifier circuit (6) that amplifies the audio signal from the microphone (4) or the pilot signal from the pilot oscillator (5);
F
It has a transmitting circuit (7) that transmits an M-modulated and FM-modulated carrier wave from the antenna (1).

° The pilot oscillator (6) oscillates for a few seconds at the beginning and end of a call to generate a pilot signal. In addition, as shown in Figure 12, the base unit has an antenna (8) connected to a receiving circuit (9), and an amplification circuit in which the audio signal received by the receiving circuit (9) is supplied via a low-pass filter. Circuit 0 sends the audio signal amplified by the amplifier circuit (b) to the telephone line (Lt
) (Lt), a vibration lift transformer (2) that transmits to
Telephone line (Lt) (amplifier circuit (to) that amplifies the voice signal supplied from L through the hybrid transformer υ,
The carrier wave is F with the audio signal amplified by the amplifier circuit (2).
A transmitting circuit 0. which modulates M and transmits from the antenna (8).
and a relay (to) that closes the telephone line (L,) (L,)
It is equipped with a control circuit for controlling. The control circuit detects the signal from the IFRK set squelch of the receiving circuit (9), and detects the pilot signal obtained from the signal output circuit 11 (b), which generates the first control signal, and the low-pass filter [phase]. and a pilot detection circuit O8, D that generates a second control signal.
Type 7 flip flop (2), D type flip 7
Output signal of 0 tube (2) and pilot detection circuit (to)
and an inverter (2) for inverting the output signal from the second control signal and applying it to the relay (2).

Next, the operation of the wireless telephone according to the present invention will be explained. After making a call to the caller from the handset, the handset is placed in the operating state 111 by, for example, switching a switch (not shown).

The pilot oscillator (5) operates for several seconds and oscillates a pilot signal. The pilot signal is amplified by the amplifier circuit (6), and is applied to the transmitter circuit (7) to FM modulate the carrier wave.
The FM modulated carrier wave is transmitted from the antenna (1). The transmitted carrier wave is received by the receiving circuit (9) via the antenna (8) of the base unit, and the receiving circuit (9) performs frequency amplification, frequency conversion to an intermediate frequency, intermediate frequency amplification, and detection. detect the pilot signal. By the way, when the carrier wave is received, a signal is generated by the squelch of the IF stage of the receiving circuit (9) and is applied to the signal detecting circuit (b), and the signal detecting circuit αη generates a first control signal at a high level. The first control signal is applied to the °C diode through the inverter and turns on the diode, which discharges the charge that had been charged in the capacitor and sets the flip-flop's reset switch to a low level. shall be. At this time, the pilot signal is also applied to the pilot detection circuit from the low-pass filter, so that the pilot detection circuit generates a second control signal at a low level. As a result, the charge in the capacitor (E) is rapidly discharged and a clock pulse is applied to the clock signal (CK). Therefore, D type flip-frog α9 is set and the output terminal (Q) is set to high level. The output signal generated by the high level is added to the NAND circuit adK together with the second control signal from the pilot detection circuit (to).The second control signal is at the front level that the pilot signal is transmitting, Since the signal disappears immediately and becomes high level, the S/D circuit (1)
The output signal of becomes low level, and the output signal is supplied to the relay (to) via the inverter (2), and the output signal of the relay (to) becomes low level.
) to close the telephone line. In this way, the relay (to) is not operated while the pilot signal is being transmitted,
The reason why the relay (to) is activated after the pilot signal disappears is to prevent the relay (to) from being activated by the conventional method of always transmitting a pilot signal during a call. be. After configuring the relay (2) and closing the telephone line as described above, when the dial signal generator (not shown) of the handset is operated to generate a dial signal, the dial signal is sent to the amplifier circuit (6). After being amplified by the transmitter circuit (7) K, the carrier wave is FM modulated and transmitted from the antenna (1). At this time, unlike the prior art, the transmitting circuit (7) K receives only a dial signal without adding a pilot signal, so that the carrier wave can be sufficiently FM-modulated with the dial signal. When the base unit receives the carrier wave FM modulated by the dial signal, it is amplified and detected in the receiving circuit (9), demodulated by the receiving circuit (9) in the same way as the carrier wave FM modulated by the pilot signal, and then the dial signal is demodulated by the low pass filter (G). It is supplied to the hybrid transformer (2) via the amplifier circuit (b), and the telephone line (LL) (L) is supplied from the hybrid transformer (2).
t) and communicated to the calling party.

When the caller responds and transmits a message, the message is transmitted from the telephone line (LL) (Lt) to the amplifier circuit 03 via the hybrid transformer (2), where it is amplified and supplied to the transmitter circuit α4, which modulates the carrier wave with FM. antenna (8)
Send from The transmitted carrier wave is supplied to the receiving circuit (3) K from the antenna (1) of the handset, and performs frequency conversion, amplification, detection, etc. to demodulate the audio signal and drive the speaker (2). You can listen to the caller's message. When you listen to the message and speak into the microphone (4) the message to be transmitted to the caller, the message is converted into an audio signal, amplified by the amplifier circuit (6), and transmitted to the carrier wave by the transmitter circuit (7). It is FM modulated and transmitted from antenna (1).

The carrier wave FM modulated by the message is demodulated by the receiver circuit (9) of the base unit to generate an audio signal. This audio signal passes through a hybrid transformer (B) and then connects to a telephone line (LL) (
LT) and is transmitted to the caller, making a 5-call call.

Since carrier waves are constantly being transmitted from the handset during a call, the signal detection circuit generates the first control signal.

Since the reset terminal ■ of the D type flip-flop (6) is held at low level, the D type flip-flop (
6) is held in the set state and the relay (to) continues to operate. However, when the call ends and the handset is placed in a standby state, the carrier wave disappears, so the first control signal from the signal detection circuit Qη also disappears. Then, the diode wire is turned off and the capacitor (c) starts charging through the resistor (to), and the resistor (2)
and: D after about 10 seconds due to the time constant of I7 capacitor (c)
Since the reset terminal (■) on the edge of the type flip-flop is set to high level, the D-type flip-flop o9 is reset and the output terminal (Q) is set to low level, so the relay (to) is deactivated and the telephone line is opened. The phone line can be released from K only by putting the handset into standby mode, but it is necessary to take a long time as mentioned above to prevent malfunctions.Therefore, when putting the handset into standby mode, K can also immediately open the telephone line by oscillating the pilot signal for a few seconds.That is, by oscillating the pilot signal at the end of the call.

The carrier wave is modulated and transmitted in the same manner as described above. Then, in the base unit, the receiving circuit (9) demodulates the signal, and the pilot detection circuit (to) generates a second low-level control signal, turns off the diode (2), and transfers the charge stored in the capacitor through the resistor. After about 1 second of discharging and depending on the time constant of the resistor and capacitor, the inverter output is changed from low level to normal level and applied to the reset terminal (2) through the diode (2), and the reset terminal [present] is set to high level. , reset the D type flip-flop (to), deactivate the relay (to), and open the telephone line.

(G) Effects of the Invention As described above, the radio telephone of the present invention is provided with a signal detection circuit for detecting a received signal and a pilot detection circuit in the base unit, and detects the carrier wave etc. transmitted from the handset during a call. The reset terminal of the flip-flop is held at a low level, the pilot signal that is sent momentarily at the start of a call is detected by the pilot detection circuit, and a clock pulse is applied to the input terminal of the flip-flop to generate a 7-lip 70-bit signal. Since the flip-flop is set to -1
Once set, it will set and continue operating the relay even if there is no pilot signal. Therefore, since a pilot signal is not required to maintain the telephone line as in the prior art, it is sufficient to modulate the 1W1 transmission wave with only the voice signal, so that the degree of modulation can be increased. Also, since the relay operates by gating the output signal of the flip 70 tube and the signal from the pilot detection circuit, malfunction can be prevented. Furthermore, by sending a pilot signal at the end of a call, it is possible to reset the flip-flop and open the telephone line, but if you forget, even a trap detects that the carrier wave has disappeared and resets the flip-flop. , I never forget to open the phone line.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a handset of the wireless telephone of the present invention, and FIG.
The figure is also a block diagram of the base unit of the wireless telephone according to the present invention. (9)...receiving circuit, α...transmitting circuit, (to)
···relay. Curve...control circuit, αη...signal detection circuit, (to)...pilot detection circuit, (2)...D type flip-flop, (1)...NAND circuit.

Claims (1)

[Claims] (1) In a device that has a base unit connected to a telephone line and a slave unit that can communicate with the base unit wirelessly, the base unit is equipped with a signal detection circuit that detects a received signal, and a pilot unit that detects a pilot signal. a detection circuit, a flip-flop whose reset terminal is supplied with the signal of the signal detection circuit and the signal from the pilot detection circuit, and whose input terminal is supplied with a clock pulse signal generated by the signal from the pilot detection circuit; and the flip-flop. 1. A radio telephone comprising: a gate circuit for gating the output signal from the pilot detection circuit and the signal from the pilot detection circuit; and a relay operated by the output signal from the gate circuit to close a telephone line.