SU1497758A1 - Demodulator of phase-shift keyed signals - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to increase the resolution of the device by demodulating signals with phase difference manipulation both by 180 ° and ± 90 °. The device contains resonators 1 and 7, full-wave rectifiers 2 and 8, low-pass filters 3 and 9, threshold blocks 4 and 10, element OR 5, and frequency doubler 6. The phase-manipulated signal is fed to the inputs of the resonator 1 and doubler 6. When the phase jumps by 180 °, the envelope of the signal at the output of the resonator 1 drops to zero. By removing the phase jumps by 180 ° by the doubler 6, the envelope of the signal at the output of the resonator 7 will not change in this case. With a phase jump of ± 90 °, the envelope of the output of resonator 1 varies slightly, whereas due to the conversion of the magnitude of the phase jump by doubler 6, the envelope of the output of resonator 7 tuned to the second harmonic of the input signal drops to zero. To highlight the envelope, the output signals of the resonators 1 and 7 are rectified, smoothed, and through threshold blocks 4 and 10 arrive at the element OR 5, where they are combined. As a result, each phase jump in the input signal leads to the appearance of a pulse at the device output. 2 Il.

Description

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The invention relates to telecommunications and can be used in data transmission equipment with double phase difference manipulation.

The purpose of the invention is to increase the resolution of the device by demodulating signals with both phase difference manipulation by 180 and ± 90 °.

FIG. 1 shows the structural electrical circuit of the proposed device; in fig. 2 - timing diagrams for the operation of the device.

The device contains the first resonator I, the first full-wave rectifier 2, the first low-pass filter 3, the first threshold unit 4, the element OR 5, the frequency doubler 6, the second resonator 7, the second full-wave rectifier 8, the second low-pass filter 9 and the second threshold block 10.

The device works as follows.

Phase-manipulated signal (Fig. 2a) is fed to the inputs of the resonator 1 and frequency doubler 6. When the phase jumps by 180, the envelope signal at the output of resonator 1 falls almost to zero (Fig. 26). By removing the phase jumps by 180 by the frequency doubler 6 (Fig. 2c), the envelope of the signal at the output of the resonator 7 in this case does not change (Fig. 2d). On the contrary, when the phase jumps, the envelope of the signal at the output of the resonator 1 changes only slightly ( 2b), while due to the conversion of the phase jump value by the Doubler 6 frequency (FIG. 26), the envelope of the signal at the output of the second resonator 7, tuned to the second harmonic of the input signal, falls almost

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to zero (Fig. 2d). In order to isolate the envelope, the output signals of resonators 1 and 7 are rectified by rectifiers 2 and 8 and are smoothed by low-pass filters 3 and 9, respectively (Fig. 2e and Fig. 2e). The selected envelope signals (Fig. 2d and Fig. 2e) are fed to threshold blocks 4 and 10, the output signals of which (Fig. 2g and Fig. 2i) are combined with an OR 5 element, with the result that each phase jump in the input signal leads to the appearance of a pulse at the output of the device (Fig. 2k).

Thus, the device detects in the input signal not only phase jumps by 180, but also by t90, i.e. its phase resolution is doubled.

Claims (1)

Invention Formula A device for demodulating phase-shifted signals, containing a first resonator connected in series, a first full-wave rectifier, a first low-pass filter and a first threshold unit, which, in order to increase the resolution by demodulating signals as a phase difference manipulator by 180 and i90, serially connected frequency doubler, second resonator, second full-wave rectifier, second low-pass filter, second threshold unit, and And element And, the second input of which is connected to the output of the threshold Dervo block, the input of the first resonator is coupled to the input of a frequency doubler and is entering the device output is output kptorogo OR element.