SU1095439A1 - Phase-shift keyed signal demodulator - Google Patents

Abstract

1. A PHASE-MODULATED SIGNAL MODULATOR containing a series-connected first multiplier, an adder to the second input of which the output of the second multiplier is connected, and an amplitude limiter, as well as the first low-pass filter and a pulse shaper, which are different in that suppression of spurious components, a second low-pass filter and two attenuators are introduced, the input of the pulse shaper is connected to the input of the first low-pass filter, the output of which through the first attenuator connected to the input of the second multiplier and the output of the pulse shaper via a serially coupled second lowpass filter and an attenuator connected to the input of the second multiplier. 2. The modulator according to claim 1, characterized in that the pulse shaper consists of two threshold blocks, an adder and a series-connected differentiator and attenuator, the output of which is connected to the inputs of the threshold blocks, the outputs of which I are connected to the inputs of the adder, the output of which is output shaper (L pulses, the input of which is the input of the differentiator.

Description

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The invention relates to telecommunications and can be applied in phase telegraphy transmitters to modulate a carrier.

A phase modulator signal modulator is known that contains conversion units, phase modulators, a phase shifter and an adder 1.

A disadvantage of the known modulator is the presence of spurious components in the spectrum of the generated signal.

A phase modulator signal modulator is known that contains a series-connected first multiplier, an adder, to the second input of which the output of the second multiplier is connected, and an amplitude limiter, as well as a first low-pass filter and a pulse shaper 2.

The disadvantage of this modulator is that the parasitic components of the quadrature channel appear in the spectrum of the generated signal, worsening the energy relationships of the transmitter. In addition, this module is characterized by low stability of parameters.

The purpose of the invention is to reduce the width of the signal spectrum by suppressing the parasitic components.

The goal is achieved by the fact that the modulator of the phase-shift keyed signal containing the first multiplier connected in series, the adder, to the second input of which the output of the second multiplier is connected, and the amplitude limiter, as well as the first low-pass filter and the pulse shaper, have introduced a second low-pass filter and two an attenuator, wherein the input of the pulse generator is connected to the input of the first low-pass filter, the output of which is connected to the input of the second multiplier through the first attenuator, and you od pulse shaper via a serially coupled second lowpass filter and an attenuator connected to the input of the second multiplier.

Moreover, the pulse shaper consists of two threshold blocks, an adder and serially connected differentiator and attenuator, the output of which is connected to the inputs of threshold blocks, the outputs of which are connected to the inputs of the adder, the output of which is the output of the pulse shaper, the input of which is the differentiator.

FIG. Figure 1 shows the functional electrical circuit of the modulator; in fig. 2 lines of voltage, which give his work.

The phase-shift keyed signal modulator contains the first 1 and second 2 multipliers, the adder 3, the amplitude limiter 4, the first low-pass filter 5, the second low-pass filter 6, the first 7 and second 8 attenuators, and the pulse shaper 9, and the shaper 9 contains pulses blocks 10 and 11, the adder 12, the differentiator 13 and the attenuator 14.

The modulator operates as follows.

The input information signal (Fig. 2a) of the data is fed to the input of the low-pass filter 5 and to the input of the differentiator 13. Pulses from the output of the differentiator 13 (Fig. 26) are fed through the attenuator 14 to the inputs of two threshold blocks 10 and 11. Output pulses of the threshold blocks 10 and 11 are summed at the adder 12 (Fig. 2c) and fed to the input of the second low pass filter 6. Filters 5 and 6, with identical parameters, filter the signals in the AF / 2 band, where AF is the spectrum band at the output of the modulator.

The voltages from the outputs of the first 5 and second 6 low-pass filters (Fig. 2d, e) through the first 7 and second 8 attenuators are fed to the inputs of multipliers 1 and 2 installed in the in-phase and quadrature channels, respectively. The output voltages of multiplier 1 (Fig. 2e are amplitude, Fig. 2g is phase) and multiplier 2 (Fig. 2h is amplitude, Fig. 2i is phase) are fed further to adder 3, the voltage from which output (Fig. 2k) enters the amplitude limiter 4.

A phase-manipulated signal with a constant envelope and limited spectrum appears at the input of the amplitude limiter 4 (Fig. 2n is the amplitude, Fig. 2m is the phase). Using attenuators 7, 8 and 14, you can set the minimum levels of spurious components and the carrier in the spectrum of the resulting signal.

Depending on the threshold blocks 10 and 11, the polarity of the pulses in the quadrature channel of the modulator may remain unchanged or change in accordance with the sign of the derivative of the input information signal. At the same time, the phase of the output signal vector varies with respect to the reference signal vector in the range of O-180-0 ° or in the range of 0-180-360 °.

The technical and economic effect of the modulator consists in reducing the spectrum of the output signal with a constant envelope, reducing the level of parasitic components, eliminating unstable and complex in the technical implementation of analog elements.

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FIG. 2

Claims (2)

1. A PHASOMANIPULATED SIGNAL MODULATOR comprising a first multiplier connected in series, an adder, to the second input of which a second multiplier output is connected, and an amplitude limiter, as well as a first low-pass filter and a pulse shaper, characterized in that, in order to reduce the signal spectrum width by suppression of spurious components, a second low-pass filter and two attenuators are introduced, while the input of the pulse shaper is connected to the input of the first low-pass filter, the output of which is through a first attenuator connected to the input of the second multiplier and the output of the pulse through the series connected second lowpass filter and an attenuator connected to the input of the second multiplier. 2. The modulator in π. 1, characterized in that the pulse shaper consists of two threshold blocks, an adder and series-connected differentiator and attenuator, the output of which is connected to the inputs of the threshold blocks, the outputs of which are connected to the inputs of the adder, the output of which is the output of the pulse shaper, the input of which is differentiator input. figure 1>