SU471680A1 - Device for receiving frequency-controlled signals - Google Patents

Description

one

The invention relates to telegraph communication, in particular, to devices for receiving frequency-manipulated signals.

A known device for receiving frequency-controlled signals, comprising a series-connected limiter, a frequency detector and a phasing node, the integrator whose control input is connected to the output of the phasing node has insufficient signal immunity for receiving signals, especially in multipath channels.

The purpose of the invention is to improve noise immunity.

This is achieved by the fact that in the proposed device the input of the limiter is connected to the signal input of the integrator through an additional frequency detector, the control input of which is connected to the corresponding output of the phasing node; In addition, in the additional frequency detector, the separation filters are made switched, their control inputs are combined and are the control input of the additional frequency detector.

The drawing shows a block diagram of the proposed device.

To the output of the receiver 1 radio signals, limiter 2, frequency detector 3 and phase unit 4 are connected in series. Parallel to this circuit, to the output of the receiver

1 a second circuit is connected, consisting of a series-connected additional frequency detector 5, which contains switched dividing filters 6 and

7, the rectifiers 8 and 9, and the subtraction circuit 10, the integrator 11, and the output device 12. The filters B and 7 and the control input of the integrator 11 are connected to the corresponding outputs of the phasing node 4.

The device works as follows. The frequency-manipulated signal from the output of receiver 1 through limiter 2 is fed to frequency detector 3 and then to the phasing node 4. At the same time, the signal from the output of receiver 1 is successively fed to the switched separation filters b and 7 of the additional detector 5, rectifiers 8 and 9 and to the circuit 10 subtraction. From the output of this circuit, the pulse signal is fed to the integrator 11, which is used to determine the sign of the parcels in the interval of its duration.

From the output of the phasing unit 4, at the end of each parcel, the control inputs of the switched filters 6 and 7 receive impulses of the appropriate duration to extinguish the residual stresses from the previous parcels and lock the filter inputs for the time of the parcel blocking due to multipath. At the same time, from the phasing node 4, short pulses at the end of each premise are fed to integrator 11 for its discharge. Using the bit pulses, the output device 12 forms rectangular premises corresponding to, polarity and nominal duration.

Subject invention

Claims (2)

1. A device for receiving frequency-mannpulated signals, comprising a series-connected limiter, a frequency detector and a phasing node, the output of which Connected to the integrator's control input, characterized in that, in order to increase noise immunity, the limiter input is connected to the signal input of said integrator via an additional frequency detector, the control input of which is connected to the corresponding output of the phasing node. 2. The device according to claim 1, characterized in that in the additional frequency detector the separation filters are made switched, their control inputs are combined and are the control input of the additional frequency detector.