SU531300A1 - Device for demodulating phase shift keying signals - Google Patents

Description

one

The invention relates to radio engineering, can be used in radio receiving devices with phase shift keying (FM).

A device for demodulating signals with Φ, containing an input circuit, the output of which is connected through the phase inverter to the first inputs of the elements I and through a coherent heterodyne to another input of the first element I, as well as serially connected subtractive cascade, integrator and decision unit, is known.

However, in the known device, the parcels of one polarity prevail over the parcels of the other.

The purpose of the invention is to increase the reliability of receiving messages.

In the proposed device, the output of a coherent heterodyne through an inverter is connected to another input of the second element AND, and the outputs of both elements AND are connected to the inputs of the OR element, the output of which is connected to the first input of the subtracting stage through an integrating circuit, and to the second input through a series-connected inverter and another integrating circuit.

The drawing shows a block diagram of the device.

Input circuit 1 through phase inverter 2 is connected to the first and input elements And 3.4 and through coherent local oscillator 5 - to another input of the first element And 3. Output local oscillator 5 through inverter 6 is connected to another input element And 4, and the outputs of elements And connected to the inputs of the element OR 7. The output of the element OR 7 is connected to the first input of the subtractive stage 8 via an integrating circuit 9, and to the second input through a serially connected inverter 10 and another integrated circuit 11. The output of the subtractive stage 8 is connected to the output of the device o United integrator 12 and decision block 13.

The device works as follows. Elements And 3.4 perform the operation of a full-wave logical coincidence of the FM signal and the signal from the coherent local oscillator 5. The results of the logical coincidence are combined on the element CLI 7. On the integrating circuits 9 and 11 there are two antiphase, but identical in form voltage on one of their voltage grows exponentially to the voltage of the source, and on the other, because the law falls to zero. With the same constant charge and discharge of the integrating circuits 9 and i 1, the inputs of the subtracting cascade 8 are affected by two antiphase signals, with ;-) iOtv their polarity changes in accordance with the law of manipulation.

At the output of the subtracting stage 8, the signal changes polarity at the moments when the charge voltage on one of the integrating circuits, for example 9, is equal to the voltage ;,., The charge on the integrating circuit 11, and vice versa. The moment of time when the voltages to the 9 inputs of the subtracting cascade 8 are the same depends only on the constant charge and discharge i.ieHH of the integrating circuits 9, 11.

Claims (1)

Invention Formula A device for demodulating signals with phase shift keying, containing an input circuit, the output of which is connected through the phase inverter to the first inputs of the AND elements and through a coherent local oscillator to another input of the first AND element, as well as the sequentially connected subtractive cascade, the integrator and the decisive unit, characterized by that, in order to increase the reliability of receiving messages, the output of the coherent local oscillator through the inverter is connected to another input of the second element AND, and the output of both elements AND are connected to the inputs of the element OR, the output to orogo coupled to the first input of the subtractor stage via an integrating circuit and the second input - the inverter via a series connection and the other integrating circuit.