SU907855A1 - Device for shaping frequency-modulated signals - Google Patents

Description

(54) DEVICE FOR FORMATION

FREQUENCY MODIFIED SIGNALS

one

The invention relates to radio engineering and can be used in radio communications, radiolocation, radio telemetry, radio control to form frequency-modulated sinusoidal oscillations.

A device for generating frequency-modulated signals is known, comprising a generator, the output of which is connected via a phase shifter to the first input of the first multiplier, the output of which is connected to the first input of the first adder, the second input of which is connected to the output of the second multiplier 1.

However, the known device does not provide sufficient formation accuracy.

The purpose of the invention is to improve the formation accuracy.

. To achieve this goal, a device for generating frequency-modulated signals containing a generator, the output of which is connected via a phase shifter to the first input of the first multiplier, the output of which is connected to the first input fie) Boro of the adder, the second input of which is connected by the output of the second multiply. 1,; (5e; 1eny memory blocks, converters

"Code-analog, counter, converter" voltage - frequency, discriminator, second adder and quadrator, the output of which is connected through the converter "voltage-frequency connected to the counter input, you. the stroke of which is connected to one input of the second adder and to the inputs of the first memory block, the outputs of which through the first converter are code-analog connected to the first input of the second multiplier, the second input of which is connected to the generator output, and the input of the quadrator is connected to the discriminator input connected to the input of the second memory block, the outputs of which are connected to other inputs of the second adder, the outputs of which through the third memory block are connected to the inputs of the second converter "analogue code, whose output pogo connected to the second input of the first multiplier. The drawing shows a structural electrical circuit of the proposed device.

2Q A device for generating frequency-modulated signals contains a quadrant K converter 2 "voltage - frequency, counter 3, first memory block 4.

an adder 5, a discriminator 6, a second memory block 7, a third memory block 8, two converters 9 and 10 "analogue code, two multipliers H and 2, a phase shifter 13, a generator 14 and an adder 15.

A device for generating frequency-modulated signals operates as follows.

The modulating signal goes to quad 1, the output voltage of which is equal to the modulating signal modulus, as well as to discriminator 6, the output voltage of which is equal to "1", when the modulating signal is more or equal to zero and logical "O - at modulating signal less than zero . The output voltage of the quadrant 1 is fed to the input of the converter 2, the output of which is a sequence of pulses whose repetition frequency is directly proportional to the modulating voltage module. The pulse sequence is fed to the input of the counter 3, where the pulse stream is converted into a binary code, the repetition period of which is proportional to the pulse frequency. The sequence of code words from the outputs of counter 3 is fed to the first group of inputs of adder 5 and to the address inputs of block 4, the truth table of which is designed so that the sequence of address code combinations chooses an output sequence of higher magnitude, the values of which are proportional to the instantaneous amplitude of the harmonic signal his period. This sequence of code combinations is converted into a harmonic signal using converter 9. The repetition period of the code combinations of the address of block 4 is equal to the repetition period of the code combinations of the harmonic signal at its output. The same applies to block 8. The signal from the output of the discriminator 6 is fed to the address input of block 7. If the logical input "O" is sent to the address input, the n-bit word K is selected, which is fed to the second group of inputs of the adder 5, which performs summation of the current code from the outputs of counter 3 with the Ko code. The Ko value is chosen in such a way that its summation with the current code gives a negative shift by 4 times the repetition of code words from the output of the counter 3. If the logical address of the block 7 goes to logical 1 then the code Ki is selected, otorrhea Referring to the current summing at the adder 5 code gives a positive shift of 1/4 of the repetition period of the output current of the adder 5. code values codewords Co and K are calculated by the formulas:

Ko0.75- (); K, 0.25- () ,.

The output code words affect the address inputs of block 8, the truth table of which is similar to the truth table of block 4. Thus, the output of converter 10 also forms a harmonic signal with a phase different from the phase of the harmonic signal removed from the output of converter 9 by ± Jt / 2. The signals from the outputs of the converters 9 and 10 are fed to the first inputs of the multipliers 11 and 12. To the second input of the multiplier 11

A high-frequency signal with a frequency fj from the generator 14 is fed through the phase shifter 13 n / 2 to the second input of the multiplier 12. The signals from the outputs of the multipliers 11 and 12 are summed in the adder 15, the output of which is the output of the frequency-modulated signals generator.

The proposed implementation of a device for generating frequency-modulated signals allows to obtain highly stable frequency-modulated signals with a low level of parasitic amplitude modulation, which, in turn, leads to an increase in the noise immunity of information transmission and processing systems.

Claims (1)

Invention Formula A device for generating frequency-modulated signals, comprising a generator, the output of which is connected via a phase shifter to a first input of a first multiplier, the output of which is connected to a first input, a first adder, a second input of which is connected to an output of a second multiplier, in order to improve the shaping accuracy, memory blocks entered; converters “code-analogue, counter, converter“ voltage-frequency, discriminator, second adder and quadrator, the output of which through the converter “voltage- 0, the frequency is connected to the input of the counter, the output of which is connected to one of the inputs of the second adder and to the inputs of the first memory block, the outputs of which are connected through the first converter "code-analog to the first input of the second multiplier,  the second input of which is connected to the generator output, and the input of the quadr is connected to the input of the discriminator, the output of which is connected to the input of the second memory block, the outputs of which are connected to other inputs of the second adder, the outputs of which through the third memory block are connected to the inputs of the second transducer analogue, the output of which is connected to the second input of the first multiplier. Sources of information taken into account in the examination .1. Alekseenko A.G. Basics of microcircuitry, M., “Soviet radio, 1977, p. 321 (prototype).