JPS59110233A - Digital radio transmitter - Google Patents

Abstract

PURPOSE:To reduce the size of a device, to decrease the frequency of transmission, and to save electric power in transmission by controlling the transmission by a fixed differential modulation type binary/ternary converter. CONSTITUTION:Fixed differential modulation is imposed upon an input voice by a primary modulator 2 to obtain a binary digital signal, which is then converted into a ternary fixed differential modulated signal by the fixed differential modulating binary/ternary converter 6. A transmission switch 7 is controlled by the output of the converter 6 to determine whether transmission is performed or not, and the output of the switch 7 is supplied to an antenna through a power amplifier 4 during the transmission.

Description

[Detailed description of the invention] This invention relates to digital radio transmitters.

(3) is a first-order modulator (
2) is a secondary modulator that wirelessly modulates the digital signal output from 2), (4) is a power amplifier, and (5) is an antenna.

Next, the operation will be explained. The audio supplied from the audio terminal (1) is converted into a digital signal by the primary modulator (2). The primary modulator (2) mainly uses differential modulation. The digital signal is converted to radio frequency by a secondary modulator (3). F as the secondary modulator (3)
There are SK, PSK modulators, etc. Since the radio frequency modulated signal is amplified by the power amplifier (4), the SSB
Unlike wireless devices, they have to transmit voice pauses during a conversation, consume a large amount of power during transmission, and are more likely to be monitored by radio waves than by other parties.

This invention was made to eliminate the above-mentioned drawbacks of the conventional ones, and aims to provide a digital radio transmitter that can inhibit transmission using the characteristics of differential modulation during pauses in conversation. .

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, the same symbols as in FIG. 1 indicate the same elements, and in this case, the primary modulator (2) is a constant difference modulator. In addition, (6) is a differential modulation binary/ternary converter, which is a first-order modulator (secondary modulator).
) is used to convert a binary differential modulation signal into a three-level differential modulation signal. (7) is a transmission switch which prohibits transmission when the ternary differential modulation signal is 0.

Next, the operation will be explained. In FIG. 2, audio supplied from an audio input terminal (1) is modulated by a primary modulator (2) and converted into a binary digital signal. Binary differential modulation signal is converted to constant differential modulation binary/ternary converter (6)
It is converted into a three-value constant difference signal by. The voice pauses are 1.0, 1, 0, etc. in a binary constant difference signal.・・・・・・
...However, in the three-level differential modulation signal, 0, 0, 0
．． It becomes... Therefore, by counting or integrating the 0 value, it is possible to supply this to the transmission switch (7) as a transmission prohibition signal when the voice is paused. The binary differentially modulated signal differentially modulated by the primary modulator (2) is converted into a radio frequency by the secondary S-modulator (3) and supplied to the transmission switch (7). This transmission switch (7) uses a constant difference modulation binary/ternary converter (6).
It is determined whether or not to transmit based on the output of the .During transmission, the signal is supplied to a power amplifier (4), amplified in power, and then radiated from the antenna (5).

Note that although the above embodiment shows an example in which a differential modulation method is used for the primary modulator, this primary modulator may use other digital modulation methods, and in this case, the audio signal is differentially modulated. After performing binary/ternary conversion, this can be used as a transmission control signal.

In this case as well, the simplicity of the differential modulator is utilized to downsize the device.

As described above, according to the present invention, since the transmission control is performed using a differential modulation binary/ternary converter, the device can be made inexpensive and compact, and the frequency of transmission can be reduced. This has the effect of saving power consumption during transmission, and making it difficult for anyone other than the target communicator to monitor the radio waves.

FIG.

(1)...Audio input terminal, (2)...Primary modulator,
(3)...secondary modulator, (4)...power amplifier, (
5)...Antenna, (6)...Constant modulation binary/ternary converter, (7)...Transmission switch.

Agent Shin Kuzuno - Figure 1 Figure 2 Bow

Claims (1)

[Claims] (1) A primary modulator that digitally modulates the audio input, a secondary modulator that wirelessly modulates the output of the primary modulator, and a differential modulator that performs binary/ternary conversion of the differential modulation signal of the audio input. A modulation binary/three-value □ converter, a transmission switch that is controlled by the output of this differential liquid m2-value/three-value converter and passes or blocks the output of the secondary modulator, and a transmission switch that converts the output of this transmission switch into %.
A digital radio transmitter characterized by comprising a power amplifier that amplifies power.