Duplex voice communication radio transmitter-receiver
AssigneesTouhoku-Denryoku Kabushiki Kaisha, Fuji-Tekku Kabushiki Kaisha
InventorsFujio Sumi, Susumu Nakabayashi, Sakari Ohira, Kouichi Ishikawa
Life of this patent
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Abstract
A duplex voice communication radio transmitter-receiver according to the present invention is provided with a low-pass filter arranged before a time compressing device in a transmitter section for cutting off a higher frequency portion of the band of a voice signal thus to decreasing the maximum modulation frequency of the same to less than a half so that it can be operated with the use of an assigned, single frequency transmission radio wave of which frequency band is legally limited, improved in the utilization of frequencies, minimized in the delay of communication signals, and enhanced in the articulation and intelligibility of a reproduced voice sound.
Claims10
A duplex voice communication radio transmitter-receiver for use with a radio wave of one single frequency or two adjacent frequencies, comprising:
- a master station and a slave station each having a transmitter unit and a receiver unit having the same functions;
- each of said master station and said slave station including:
- a pattern generator for causing the transmitting duration and the receiving duration to be reverse to each other in the time-division pattern between the master and slave station, and
- a composite tone signal generator for producing a composite tone signal consisting of a plurality of different frequency tone signals which are continuous and have timing points to match the time-division patterns in phase;
- each of said transmitter units including:
- a time-division device for time dividing a voice signal into a series of voice signal segments,
- a time compression device for time compressing the voice signal segments to produce an intermittent voice signal, and
- a modulator device for modulating a carrier with the intermittent signal to an intermittent radio waveform which is then transmitted;
- and
- each of said receiver units including:
- a time expansion device responsive to the intermittent radio waveform for reconstructing the intermittent voice signal and time expanding it to a series of the voice signal segments, and
- a device for converting the voice signal segments back to the original voice signal by binding synchronization with the time-division pattern;
- said master station adapted for modulating the carrier by adding the composite tone signal to the time-compressed intermittent voice signal;
- and
- said slave station adapted for intercepting the radio waveform, separating the composite tone signal from the radio waveform to extract the intermittent voice signal, time expanding the intermittent voice signal to a series of the voice signal segments at the timing points of the composite tone signal, and converting the voice signal segments back to the original voice signal by binding in synchronization with the time-division pattern.
Dependencies are inferred from the claim text.