Abstract:
A device for processing digital pulse code modulated signals comprises means for sampling and quantizing the signal at a frequency which is a multiple of that at which the digits are transmitted. These samples are stored and summed after each sampling operation. The result of the summing is fed to reference threshold devices to generate the requisite parameters for the control of the receiver, by means of logic circuits.
Abstract:
A radio communications system comprising at least one master station and a plurality of slave stations in two-way frequency-hopping communication therewith. For telephony, speech is digitally encoded. Digital data is transmitted in packets using successive bursts at different frequencies separated by intervals of silence. Each slave station has its own frequency-hopping pattern independent of the patterns of the other slave stations but sharing a common pool of available frequencies. The master stations are capable of generating any of the slave station patterns instantly. The master stations broadcast network time information for synchronization purposes, and the slave station patterns are determined by a combination of a slave station identification number and network time.
Abstract:
A circuit determines whether the signal transmitted by a variable-gain amplifier comprises information or not. If it comprises information, its level is regulated, by comparison with a first reference signal, in order to give a predetermined correct listening level at the output of the receiver. If it does not comprise any, its level is regulated, by comparison with a second reference signal, in order to give at the output of the receiver the listening level corresponding to the hearing threshold.
Abstract:
A circuit determines whether the signal transmitted by a variable-gain amplifier comprises information or not. If it comprises information, its level is regulated, by comparison with a first reference signal, in order to give a predetermined correct listening level at the output of the receiver. If it does not comprise any, its level is regulated, by comparison with a second reference signal, in order to give at the output of the receiver the listening level corresponding to the hearing threshold.
Abstract:
Stations allowing the use of directional antennas for multiple connections between a master station and each one of subordinate stations. The antenna of a master station M rotates uniformly. When it is directed towards a subordinate station S, the informations to be transmitted, compressed to this end, are transmitted bilaterally. The expansion of the compressed information received takes place regularly. If the stations are mobile, the antennas of the stations S are equipped with an acquisition and servosystem keeping it directed towards the station M.
Abstract:
A frequency jump radiocommunications system fixed station in which n receivers and n channels may be connected to p transmitters; p being less than n. A management circuit is provided on each of the n channels to provide signals indicating the active/nonactive state of each channel. A time/frequency law generator is provided on each channel to generate the jumped frequency signals. A general control circuit receives the active/nonactive signals and provides a connection control signal and provides a connection control signal assigning one of the n channels to one of the p transmitters. The general control circuit also generates a transmission authorization signal to authorize the p transmitters to transmit. The connection control signal is received at first and second connection matrices. The first connection matrix connects one of the n channels to one of the p transmitters and the second matrix connects one of the n time frequency law generators to one of the p transmitters, as designated by the connection control signal.
Abstract:
A radio communications system comprising at least one master station and a plurality of slave stations in two-way frequency-hopping communication therewith. For telephony, speech is digitally encoded. Digital data is transmitted in packets using successive bursts at different frequencies separated by intervals of silence. Each slave station has its own frequency-hopping pattern independent of the patterns of the other slave stations but sharing a common pool of available frequencies. The master stations are capable of generating any of the slave station patterns instantly. The master stations broadcast network time information for synchronization purposes, and the slave station patterns are determined by a combination of a slave station identification number and network time.
Abstract:
A radio communications system comprising at least one master station and a plurality of slave stations in two-way frequency-hopping communication therewith. For telephony, speech is digitally encoded. Digital data is transmitted in packets using successive bursts at different frequencies separated by intervals of silence. Each slave station has its own frequency-hopping pattern independent of the patterns of the other slave stations but sharing a common pool of available frequencies. The master stations are capable of generating any of the slave station patterns instantly. The master stations broadcast network time information for synchronization purposes, and the slave station patterns are determined by a combination of a slave station identification number and network time.