JPS5937744A - Annunciator of radio telephone set - Google Patents

Abstract

PURPOSE:To know that another slave equipments is in communication at a look, to prevent a transmitting circuit from being operated by mistake, and to prevent the generation of radio interference, by operating annunciating circuits of respective slave equipments while some slave equipment is in communication with a master equipment. CONSTITUTION:The master equipment is connected to a telephone circuit and radio communication between the master equipment and plural slave equipments each provided with a receiving circuit 9 and a transmitting circuit 8 is performed. The circuit 9 of every slave equipment is provided with an IF signal detecting circuit 29 and a voice output control circuit 28 which amplifies a call signal selectively. Further, a circuit monitoring circuit 36 which monitors output signals of both circuits 28 and 29 is provided. The annunciating circuit 32 consisting of a transistor 30 and a light emitting diode 31 is provided on the output side of the circuit 36 and the annunciating circuit 32 is controlled by the output of the circuit 36. Then the output of the circuit 36 goes to a level H by the output of the circuit 28 in communication of some slave equipment to radiate the diode 31, thus annunciating the state that other slave equipments are in communication. Consequently, erroneous operation of the circuit 8 by a hook switch 35 is eliminated to prevent radio interference.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a notification device for a radio telephone that wirelessly transmits and receives signals between a base unit connected to a telephone line and a plurality of slave units.

(B) Background Art Recently, in wireless telephones that have been made possible to make wireless calls by connecting a base unit to a base unit connected to a telephone line and a slave unit located at a distance, in order to increase usage efficiency, one base unit has been connected to the base unit. For this purpose, a plurality of slave units are provided.

By the way, the base unit and the slave unit are each provided with a transmitting circuit and a receiving circuit, and the transmitting circuit modulates a carrier wave with a calling signal, dial signal, or transmitting/receiving signal and transmits the radio wave, and the receiving circuit receives the carrier wave. Communication is carried out by demodulating the signal into the original signal, but the frequencies of the carrier waves transmitted from each slave device are the same. In such a device, if one handset uses another handset to transmit a carrier wave during communication, the same frequency (co-cbannel)
Interference occurs and prevents normal telephone communication.

(c) Means for solving the problem The present invention provides a notification device for a radio telephone that notifies other handsets when one handset is in use and prevents interference from occurring. This is what we provide.

The present invention will be explained below with reference to the drawings. In Fig. 1, (1) is a base unit connected to the evening 1st talk line (Ll) (Lt), ), an interface section (2) for coupling with the telephone line (Ll) (
L2) A transmitting circuit (3) that modulates the carrier wave with a calling signal and a receiving signal from the terminal 444 (5a) (5b)
. . . It has a receiving circuit (4) that demodulates the radio waves transmitted from the radio waves and extracts dial signals and reception signals, and antennas (6) and (7) that transmit and receive the radio waves. The handset (
5a) (5b)... are transmitter circuits (similar to the base unit (1)).
6), a receiving circuit (9) and an antenna QQI (II). Child units (5a) (5b) from the above-mentioned Ita 1 unit (1).
The frequency of the carrier wave transmitted to ... is f, and each slave device (
5a) (5b)... The frequencies f2 of the carrier waves transmitted to the parent device (1) are all the same frequency.

FIG. 2 shows a block diagram of the handsets (5a), (5b), etc., and the transmitting circuit (5) is connected to the microphone 021.
．． an FM modulation circuit (131, carrier wave oscillation circuit Q4) that amplifies the voice signal from the microphone 02) and FM-modulates a carrier wave generated by the voice signal;
15), the FM modulation circuit (consists of a multiplier circuit (]61 connected to 1h1, and a high frequency output circuit aη, and further includes an I
The M modulation circuit (15) receives a dial oscillator (a dial signal from the country) and a receiver circuit (a high frequency amplifier circuit + 11). a mixing circuit G101 that mixes local oscillation signals from the above and generates an intermediate frequency signal, an intermediate frequency amplification circuit (22) that amplifies the intermediate frequency signal, and detects a receiving signal and a calling signal from the amplified intermediate frequency signal G4; The amplification degree is determined by the detection circuit C2 (to), the detection circuit (low frequency amplifier circuit c24 connected to 231), and the call signal in the selective amplifier circuit c7 that amplifies the call signal in the low frequency amplifier circuit C4). a controlled audio output circuit (26);
The speaker (2'/J and the audio output control circuit that amplifies the calling signal!2+ The line monitoring circuit C is controlled by the signal from the tzi+ and the calling signal from the audio output control circuit (layer), and the transistor ((lO and light emitting diode 01) is controlled by the output signal from the line monitoring circuit (to). The line monitoring circuit (a) includes a notification circuit 021 consisting of a Noah circuit and an inverter G.1).

Next, the operation of the present invention will be explained 2. In the standby state, the hook switch 0ωC351 is in the state shown in the figure, and the hook switch 0ωC351 is in the state shown in the figure.
Only the circuit (") is in operation. When a call signal from the other party is supplied to the base unit (1) via the city 1 line (Ll) (L2) in the declining state, the call signal is sent to the base unit. The transmitting circuit (3) in (1) modulates the carrier wave, and generates the carrier wave f.

Sent with The carrier wave f1 (previous HC) is the slave unit (
5a) (5))) ... is added to the receiving circuit) and amplified by the high frequency amplification circuit 0. The mixed circuit (2)
) is mixed with the local oscillation signal and converted to an intermediate frequency signal,
The intermediate frequency amplification circuit (2) is amplified, and the detection circuit (
C), the audio signal is amplified by the low frequency amplifier circuit c24, and then supplied to the speaker (27) via the audio output circuit 12e to drive the speaker Qυ. As a result, the holders of the handsets (5a, 5b), etc. know that there is a call. After that, hook switch 01
Connect the contact piece (35a) (35a) of wholesale ω to the contact point (35b) (3
51)) to contact (35c) (35c),
When you speak into the transmitting circuit (the river is also activated. Therefore, microphone 02), the speaking voice is converted into an electrical signal, amplified by the low frequency amplifier circuit (13), and oscillated by the carrier wave oscillation circuit (14). The resulting carrier wave f2 is FM modulated by an FM modulation circuit 011), multiplied by a multiplier circuit (L[i), and transmitted from an antenna through a high frequency output circuit aη.

The transmitted carrier wave f is received by the base unit (1), and converted into the original audio signal by frequency conversion, detection, etc. in the receiving circuit (4), and after amplification, the original audio signal is 1%! (LIXL2)
is transmitted to the other party via. In this way, it is possible to make a wireless call from a remote location to a base unit connected to a telephone line.

Although the case where a calling signal is transmitted from the other party has been described above, it is also possible to call the other party from the handset.

In that case, first switch the contacts (35a) (35a) of the hook switch (1', +101) to the contacts (35c) (35c) to put the transmitter circuit (6) into operation. When a dial signal is sent, the carrier wave is FM modulated in the I''M modulation circuit (I5), and after being amplified as described above, it is transmitted from the antenna (10).The carrier wave is converted into an audio signal by the base unit (1). The reproduced dial signal is extracted and transmitted to the other party via the telephone circuit (LIXL2).

By the way, when communicating using one handset, if the transmitting circuit (6) of another handset is activated, the carrier wave f,
oscillates and interferes with the handset that is already communicating. Therefore, when a handset is used to communicate with a base unit, other handsets are notified of this fact. That is, the output of the intermediate frequency signal of the receiver circuit (off) is low level when either the calling signal or the receiving signal is received, and the output of the audio output control circuit (28) is the calling signal. When the current receiving circuit is in a standby state where neither the call number 16 nor the receiving signal is received, the intermediate frequency signal detection circuit and voice control circuit (2R) Since the output of is at high level, the line monitoring circuit 06)
The output of the transistor C3 (1) is turned off and the light emitting diode (31) does not emit light. When a calling signal from the other party is received, the outputs of the intermediate frequency signal detection circuit C and the audio output control circuit (28) both go to low level, but the output of the line monitoring circuit α remains at low level. Therefore, the light emitting diode 61) does not emit light at this time either.Next, when the first child unit is operated and communication begins, the carrier wave f transmitted from the koji machine (1) is modulated by the reception signal, so The output of the intermediate frequency signal detection circuit Q1 is held at a low level, but the output of the audio output control circuit (281) does not have a calling signal, so
Becomes a high level. Therefore, the output of the line monitoring circuit (g) should be switched to high level.

Then, the transistor 2 is turned on, causing the light-emitting diode C(1) to emit light to notify that the slave device is communicating.

餠）Effect As mentioned above, the notification circuit of the wireless telephone of the present invention is one that communicates wirelessly between a base unit and a plurality of slave units, and when the slave unit is communicating with the base unit, the notification circuit of the slave unit is operated. As a result, it can be seen at a glance that other slave units are communicating, and there is no possibility of erroneously activating the transmitter circuit and causing interference.

[Brief explanation of drawings]

Fig. 1 is an overall block diagram of a wireless telephone according to the present invention;
The figure is a circuit diagram of the main part of the present invention. (9)...Reception circuit, C281...Audio output control circuit, (29)...Intermediate frequency signal detection circuit, ('(+1...Light emitting diode, (3(9...)
・Line monitoring circuit.

Claims (1)

[Claims] (1) A transmitting circuit and a receiving circuit are provided for the base unit connected to the telephone line trap and the multiple slave units located apart from the base unit, respectively, and the transmitting circuit transmits audio signals such as a calling signal or an answering signal. In the apparatus for transmitting a modulated carrier wave and demodulating the carrier wave in a receiving circuit to reproduce an audio signal, the receiving circuit of the handset includes an intermediate frequency signal detection circuit for detecting an intermediate frequency signal, and an audio signal for selectively amplifying a calling signal. an output control circuit, a line monitoring circuit that monitors the output signals of the intermediate frequency signal detection circuit, and the audio output control circuit; and a line monitoring circuit that operates based on the output signal of the line monitoring circuit when the base unit and other slave units communicate. A notification device for a radio telephone equipped with a notification circuit.