SU862391A2 - Multi-frequency signal receiver - Google Patents

Description

(54). RECEIVER OF MULTI-FREQUENCY SIGNALS

one

The invention relates to telecommunication engineering and can be used in telephone communication systems for receiving subscriber number signals transmitted by a multi-frequency code.

According to the main author. swith No. 376904 is known a multi-frequency signal receiver comprising an amplifier with automatic gain control, the output of which is connected in parallel to a chain of series-connected band-pass filters, detectors, gates and triggers, the outputs of which are connected to the inputs of the information processing unit connected to the second inputs of the triggers. The signal duration analyzer and signal interval analyzer are simultaneously connected to other valve inputs via the differentiating node, the output of the latter is connected to the input of the Signal Duration Analyzer, collecting circuits and coincidence circuits, while the outputs of the first two detectors are connected to the corresponding inputs of the coincidence circuit and the collective ckeMbi , and the outputs of the subsequent detectors are connected to the first inputs of the respective subsequent matching circuits and collecting circuits, the second inputs of which are under They are connected to the inputs of the previous collecting circuits, and the outputs of the coincidence circuits are connected to an additional multi-input collecting circuit, the output of which is simultaneously connected to the signal duration analyzer and to the analyzer of the interval between signals 1.

However, the known receiver has a low noise immunity.

The purpose of the invention is to increase noise immunity.

To do this, a multi-frequency signal receiver containing an amplifier with automatic gain control, the output of which is connected in parallel to the chain of

Claims (1)

15 serially connected bandpass filters, detectors, gates and triggers whose outputs are connected to the inputs of the information processing unit connected to the second triggers inputs, the signal duration analyzer and the signal interval analyzer are simultaneously connected to other valve inputs via the differentiating node Input "Reset analyzer signal duration, collective circuits and coincidence circuits, the outputs of the first two detectors are connected to the corresponding the inputs of the coincidence circuit and the collecting circuit, and the outputs of the subsequent detectors are connected to the first inputs of the respective subsequent coincidence circuits and the collecting circuits, the second inputs of which are connected to the inputs of the previous collecting circuits, the outputs of the coincidence circuits are connected to an additional multi-input collecting circuit, the output of which is simultaneously connected to the analyzer duration signal and to the analyzer of the interval between signals, introduced the element "exclusive OR, two elements AND and an additional trigger. The output of the differentiating node through the first element AND is connected to other inputs of the valves, and the outputs of the detectors are connected to the inputs of the second element AND and the exclusive OR element, the output of which is connected via an additional trigger to another input of the first element AND, and the output of the second element AND is connected to another input of additional trigger The drawing shows a structural electrical circuit of the proposed receiver. The multi-frequency signal receiver contains an amplifier 1 with automatic gain control, the output of which is connected in parallel to a chain of series-connected band-pass filters 2, detectors 3, gates 4 and flip-flops 5, information processing node 6, matching circuit 7, collecting circuits 8, additional multi-input collecting circuit 9 , analyzer 10 signal duration, analyzer 11 intervals between signals, differentiating node 12, the element “exclusive OR 13, two elements AND 14, 15 and an additional trigger 16. Receiver works as follows. In the absence of signals from the outputs of all the filters, the AND 14 element will open and the additional trigger 16 will be set to state "1, allowing the pulses to pass through the AND 15 element. When one of the filters highlights the frequency component after detection, the pulse opens the exclusive OR 13 element and sets the additional trigger 16 to the state of "O. In this case, it is prohibited to record the following information into the triggers 5. In the absence of signals from the outputs of all the filters, the trigger 16 is again set to the state "1. Thus, the selection of frequency components by filters at different times is a criterion for the presence of interference, and the receiver does not produce such information. This provides increased noise immunity and reduced false alarms from various interferences. Claims of the invention Multi-frequency signal receiver according to the author. swith No. 376904, characterized in that, in order to improve the noise immunity, an "exclusive OR" element, two AND elements and an additional trigger are introduced, the output of the differentiating node through the AND element is connected to other gate inputs, and the detector outputs are connected to the inputs of the second element And the “exclusive OR” element, the output of which through an additional trigger is connected to another input of the first AND element, and the output of the second element AND is connected to another input of an additional trigger. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 376904, cl. H 04 Q 1/36, 1971 (prototype).