Transceivers with calling devices

Claim 2

A transceiver comprising: a. a transmitting and receiving antenna; b. receiving equipment means connected to said antenna receiving a transmitted signal through said antenna, said receiving equipment comprising a cascade connection of a high-frequency amplifier, a frequency converter, a first and second intermediate-frequency amplifier and a detector; c. transmitting equipment means connected to said antenna transmitting a signal via said antenna; d. a transmission-reception transfer switch including a reception side and a transmission side according to a receiving time and a transmitting time connected to supply a bias voltage to said receiving or transmitting equipment means; e. a calling device including an output terminal generating a call signal of multiple tones consisting of a control signal formed using said receiving equipment, a switching circuit including ON or OFF condition controlled by said control signal, and an oscillation circuit including oscillation elements connected to said switching circuit in which the constant of the oscillation elements is varied by said switching circuit; f. a calling switch at said output terminal with a CALL side, thrown to the CALL side at the calling time to operate said calling device; g. a combined audio amplifier and modulator having an input terminal connected to the output terminal of said calling device including amplifying and modulating means performing an amplifying operation at the receiving time and a modulating operation at the transmitting time; and h. a combined loudspeaker and microphone connected to said combined audio amplifier and modulator, from which a calling tone and voice is derived at the receiving time and to which a voice is supplied at the transmitting time.

Claim 3

The transceiver according to claim 1 wherein said control signal generator of said calling device is so adapted and disposed as to use said first and second amplifiers, and said oscillation circuit is so adapted and disposed as to operate as an audiofrequency amplifier at the receiving time.

Claim 4

The transceiver according to claim 2, including an CR integrating circuit between said control signal generator and said switching circuit, wherein said switching circuit comprises a first transistor to the base of which there is supplied an output signal from said integrating circuit to control said first transistor to an ON or OFF condition, and said oscillator comprises a CR phase shift circuit whose impedance is varied to two values in accordance with the ON or OFF condition of said transistor and a second transistor, so as to oscillate a call signal of two frequencies.

Claim 5

The transceiver according to claim 3, including a second integrating circuit wherein said switching circuit comprises a third and fourth transistor, the base of each of which is supplied with an output signal from said first and second integrating circuits respectively to control said transistor to an ON or OFF condition, and said oscillator comprises a CR phase shift circuit whose impedance is varied to three values in accordance with the ON or OFF condition of said transistors, so as to oscillate a call signal of three frequencies.

Claim 6

The transceiver according to claim 1 wherein said control signal generator of said calling device comprises an astable multivibrator constructed using a transistor involved in said first and second intermediate-frequency amplifiers respectively and an integral circuit shaping the waveform of an output signal from said multivibrator.

Claim 7

The device according to claim 1 wherein said receiving equipment comprises a cascade connection of a high-frequency amplifier, a frequency converter, a first and second intermediate-amplifier and a detector so as to form an AGC circuit transferring an AGC signal derived from the output terminal of said detector to the input terminal of said first intermediate-frequency amplifier, said control signal generator of said calling device comprises an astable multivibrator and an integral circuit shaping the waveform of an output signal from said multivibrator, said switching circuit comprises a first transistor to the base of which there is supplied an output signal from said integral circuit to control said transistor to an ON or OFF condition, said oscillator comprises a CR phase shift oscillator whose impedance is varied according to the ON or OFF condition of said transistor and a second transistor, thereby to oscillate a call signal of multifrequencies and operate as an audiofrequency amplifier at the receiving time, said transceiver further comprising a control device having an input terminal connected to said first intermediate-frequency amplifier and an output terminal connected to said combined audiofrequency amplifier and oscillator only at the receiving time, and performing such a squelch operation as stops the operation of said audiofrequency amplifier when there does not appear said AGC signal.

Claim 8

The transceiver according to claim 6 wherein said astable multivibrator of said control signal generator is constructed using a transistor involved in said respective intermediate amplifiers.

Claim 9

A transceiver comprising: a. a transmitting and receiving antenna; b. receiving equipment means connected to said antenna receiving a transmitted signal through said antenna, said receiving equipment comprising a cascade connection of a high-frequency amplifier, a frequency converter, a first and second intermediate amplifier and a detector so as to transfer a detecting signal derived from the output terminal of said detector to the input terminal of said first intermediate frequency amplifier; c. transmitting equipment means connected to said antenna transmitting a signal via said antenna; d. a transmission-reception transfer switch including a reception side and a transmission side according to a receiving time and a transmitting time connected to supply a bias voltage to said receiving or transmitting equipment means; e. a calling device including an output terminal Generating a call signal of multiple tones consisting of a control signal generator generating a control signal, a switching circuit controlled to an ON or OFF condition by said control signal, and an oscillation circuit including oscillating elements connected to said switching circuit, in which the constant of the oscillation elements is varied by said switching circuit; f. a calling switch at said output terminal with a CALL side, thrown to the CALL side at the calling time to operate said calling device; g. a combined audio amplifier and modulator having an input terminal connected to the output terminal of said calling device including amplifying and modulating means, performing an amplifying operation at the receiving time and a modulating operation at the transmitting time; h. a control device having an input terminal connected to said first intermediate-frequency amplifier and an output terminal connected to said combined audiofrequency amplifier and oscillator only at the receiving time, and performing such a squelch operation as stops the operation of said audiofrequency amplifier when there does not appear said detecting signal; and, i. a combined loudspeaker and microphone connected to said combined audio amplifier and modulator, from which a calling tone and voice is derived at the receiving time and to which a voice is supplied at the transmitting time.

Claim 10

A transceiver comprising: a. a transmitting and receiving antenna; b. receiving equipment means connected to said antenna receiving a transmitted signal through said antenna, said receiving equipment comprising a cascade connection of a high-frequency amplifier, a frequency converter, a first and second intermediate amplifier and a detector so as to transfer a detecting signal derived from the output terminal of said detector to the input terminal of said first intermediate frequency amplifier; c. transmitting equipment means connected to said antenna transmitting a signal via said antenna; d. a transmission-reception transfer switch including a reception side and a transmission side according to a receiving time and a transmitting time connected to supply a bias voltage to said receiving or transmitting equipment means; e. a calling device including an output terminal Generating a call signal of multiple tones consisting of a control signal generator generating a control signal, a switching circuit controlled to an ON or OFF condition by said control signal, and an oscillation circuit including oscillating elements connected to said switching circuit, in which the constant of the oscillation elements is varied by said switching circuit; f. a calling switch at said output terminal with a CALL side, thrown to the CALL side at the calling time to operate said calling device; g. a combined audio amplifier and modulator having an input terminal connected to the output terminal of said calling device including amplifying and modulating means, performing an amplifying operation at the receiving time and a modulating operation at the transmitting time; h. a control device having an input terminal connected to said first intermediate-frequency amplifier and an output terminal connected to said combined audiofrequency amplifier and oscillator only at the receiving time, and performing such a squelch operation as stops the operation of said audiofrequency amplifier when there does not appear said detecting signal; and, i. a combined loudspeaker and microphone connected to said combined audio amplifier and modulator, from which a calling tone and voice is derived at the receiving time and to which a voice is supplied at the transmitting time.

Claim 11

The transceiver according to claim 8, wherein said control signal generator of said calling device comprises an astable multivibrator and an integrating circuit shaping the waveform of an output signal from said multivibrator, said switching circuit comprises a first transistor to the base of which there is supplied an output signal from said integrating circuit to control said transistor to an ON or OFF condition, said oscillator comprises a CR phase shift oscillator whose impedance is varied according to the ON or OFF condition of said transistor and a second transistor, thereby to oscillate a call signal of multifrequencies and operate as an audio frequency amplifier at the receiving time.

Claim 12

The transceiver according to claim 8, wherein said astable multivibrator of said control signal generator is so adapted and disposed as to use said respective intermediate amplifiers.