SU553724A1 - Frequency modulator - Google Patents

Description

A signal 8, a control unit 9, the control input of which is connected to one of the outputs of the imaging unit 2, and the outputs to the second inputs of the corresponding elements of comparison 3-6.

The signal input of control unit 9 is the information input of the frequency modulator. The control unit is made in the form of a reversible counter for the duration of the master cells 10-13.

Works frequency modor tor as follows.

The pulse sequence from the master oscillator 1 goes to the shaper 2, from the outputs of which the pulse sequences with different repetition frequencies go to the first inputs of the comparison elements 3-6 and to the control input of the control unit 9. When the logical zero arrives (Fig. 2a) the input of the control unit, the signal level at the output of the master cell 10 (Fig. 26) permits the passage of a pulse sequence with a certain frequency through the reference element 3 to the first input of the adder 7. When changing the field p The data signal from the logical "zero to logical" unit (Fig. 2nd) is triggered by the control unit 9. From the outputs, the time of the defining cells 11-13 is pulsed; the duration (Fig. 2c, d, e) to the second inputs of the comparison elements 4-6 and allow the passage of pulse sequences with corresponding frequencies from the outputs of the elements of comparison 4-6 to the second inputs of the adder 7 (Fig. 2e, g, h, and, moreover, Fig. 2e is for the signal from the element of comparison 3). A modulated high-frequency pulse train from adder 7 (Fig. 2k) is fed to a quasi-sinusonal signal formation unit 8, which converts unipolar pulses and a two-polar signal that is similar in shape and spectral composition to a sinusoidal (Fig. 2n).

When the polarity of the information source data signal is changed, for example, when switching from a logical "one to a logical" zero, the control unit 9 is restarted, the signals of which allow the pulse sequences with the corresponding frequencies to pass through the comparison elements 3-6 to the inputs of the adder 7. The total modulated pulse sequence enters block 8.

Entering the frequency modulator of the control unit into the circuit allows us to narrow the output signal spectrum while reducing the frequency distortions of the transmitted signal, which makes it possible to increase the reliability of received messages and speed up their delivery with the required likelihood of completion.

Claims (2)

1. A frequency modulator comprising a series-connected master oscillator and a pulse shaper having different repetition frequencies, the outputs of which are connected to an adder through appropriate comparison elements, the output of which is connected to the input of a quasi-sinusoidal signal generating unit, characterized in output spectrum while reducing frequency distortion, a control unit is inserted into it, the control input of which is connected to one of the outputs of the pulse sequence generator, and the outputs to the second inputs of the corresponding comparison elements, while the signal input of the block control is the information input of the frequency modulator. 2. A modulator according to claim 1, wherein the control unit is designed as a reversible counter. Jzl t eleven R 1Ш Lll If ig. g