SU1688381A1 - Pulse-phase discriminator - Google Patents

Abstract

The invention relates to a pulse technique and can be used in phase locking systems. The purpose of the invention is to improve accuracy and simplification. The pulse-phase discriminator contains a phase comparison unit 1 (BFS), a split RC circuit 2 and a sample storage block 3 (BVH), which includes a storage unit 4 (PZ) and a pulse shaper 5 (PI), a pulse signal with the output of the BFS due to the introduction of an RC splitter circuit is converted at the output of the BBV to a voltage proportional to the average value of this signal, and there is no multiplicative error in a wide range of frequencies of the input pulse sequences. 2 Il.

Description

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The invention relates to a pulse technique and can be used in phase locking systems.

The purpose of the invention is to increase accuracy and simplification.

Figure 1 shows a structural electrical circuit of a pulse-phase discriminator; figure 2 - timing charts of his work.

The pulse-phase discriminator contains a phase comparison unit 1, a split RC circuit 2, and a sample-storage unit 3. The inputs of the phase comparison unit 1 are connected to the sources of the reference and controlled frequencies.

The phase comparison unit 1 serves to phase the comparison of pulses of the reference and controlled frequencies and the formation of a sequence of pulses, the follow-up period of which is equal to the reference frequency, and the duration is proportional to the phase matching of the compared frequencies. The phase comparison unit 1 can be performed, for example, in the form of an RS flip-flop.

The separator circuit 2 serves to convert the output signal of the phase matching unit 1 into a pulse signal, in which there is no constant component, and can be made in the form of a series-connected capacitor and resistor.

Sampling-storage unit 3 serves to store the output signal of an RC splitter circuit 2 at the instants of arrival of pulses of a controlled frequency. Sample storage unit 3 can be made in the form of a storage unit 4 and a pulse shaper 5. The output of the pulse shaper 5 is connected to the control input of the storage unit 4, whose information input is the information input of the sample-storage unit 3.

The pulse shaper 5 serves to form (at the leading edge of the pulse at a controlled frequency) short sampling pulses and can be performed, for example, in the form of a one-shot.

The device works as follows.

The pulses of the reference and controlled frequencies are fed to the input of the phase comparison unit 1 (figure 2). The phase comparison unit 1 generates a sequence of pulses, the period of which is equal to the period Te of the reference frequency, and the duration is proportional to the magnitude of the phase mismatch of the compared frequencies. The shape of the output voltage UB of the phase matching unit is shown in Fig. 2c. If the parameters of the split RC-circuit 2 are selected so that

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This separator circuit does not distort the input waveform. In this case, the constant component in the output signal Up from the separator circuit 2 (Fig. 2) is absent and the amplitude of the negative pulse 1) 2 of the output signal is equal to the average voltage of the input signal during the period

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where U is the amplitude of the output pulses of the phase comparison unit;

20p is the duration of the output pulses

phase comparison unit;

2 Te - t is the pause duration of the output phase comparison pulses;

Since the constant component of the output of the splitter RC circuit is absent,

G1 U (Te - ri) U2 Ui + U2 U

From here

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Substituted (2) in (4), and - U2 Te - TI U2 + TI U2 ..

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The output signal of the split RC circuit 2 is fed to the information input of the sample-storage unit 3, consisting of the storage unit 4 and the pulse former 5. The latter generates short sampling pulses on the leading edge of the monitored frequency pulses, and the storage unit 4 stores the amplitude of negative pulses The output signal Uz of the split RC circuit 2 at the moments of arrival of the sampling pulses. Thus, at the output of the pulse-phase discriminator, a voltage is formed that is proportional to the phase mismatch of the compared pulse sequences (Fig. 2e).

Calculations show that the transmission coefficient of such a pulse-phase discriminator remains constant over the entire frequency range.

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The calculated dependence of the relative transmission coefficient of the device on the relative frequency

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where KN - the transmission coefficient of the device at a frequency

. . 10 fH-f. - RC. Thus, the proposed technical solution provides an increase in the

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by reducing the multiplicative error, and is simpler than the prototype, due to the absence of a delay element and a bit key. The simplicity of the implementation of the proposed technical solution allows it to be widely used in automation devices.

Claims (1)

An impulse-phase discriminator comprising a phase comparison unit and a sample-storage unit, the inputs of the phase comparison unit are connected to the sources of the reference and controlled frequencies, so that. For the purpose of increasing accuracy and simplification, a split RC circuit is introduced, the input of which is connected to the output of the phase matching unit, the output of the split RC circuit is connected to the information input of the sample-storage unit, and the control input of the sample-storage unit is connected to the source frequencies.