RU2407144C1 - Synthesiser with v-shaped frequency modulation law - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: synthesiser with V-shaped frequency modulation law includes generator of clock pulses (1), reversible counter (2), digital-to-analogue converter (DAC) (3), generator controlled with voltage (GCV) (4), comparison circuit of codes (5), constant storage unit (ROM) (6), the first frequency divider (7), phase discriminator (PD) (8), the frequency divider (9), digital computation synthesiser (DCS) (10).

EFFECT: enlarging the frequency range of synthesised signals and increasing quick action.

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Description

The invention relates to electronic computer technology and radio engineering, is intended for the synthesis of signals with frequency modulation and can be used in radar, navigation, adaptive communication systems and allows you to synthesize a signal with a V-shaped law of frequency modulation.

Known digital frequency synthesizers of frequency-modulated signals containing a reference generator, a delay unit, a permanent memory unit, a memory register, a divider with a variable division ratio, a digital storage device, a code converter, a digital-to-analog converter, a low-pass filter, a waiting multivibrator, a reversible counter and a comparison circuit [one].

Also known is a digital computer synthesizer with quadrature outputs, containing a reference generator, a delay unit, two memory registers, two digital storage devices, a divider with a variable division ratio, two code converters, two digital-to-analog converters, two low-pass filters [2].

The closest technical solution (prototype) is a VCO-based frequency synthesizer with phase-locked loop, containing a voltage-controlled oscillator, two frequency dividers, a phase discriminator and a reference (reference) generator [4].

However, well-known digital synthesizers have low speed and a relatively narrow range of synthesized frequencies. The invention allows to expand the frequency range of the synthesized signals and to increase the speed of synthesizers.

The positive effect - expanding the frequency range of the synthesized signals and increasing the speed of the synthesizers - is achieved due to the fact that in a synthesizer with a V-shaped law of frequency modulation, containing a series-connected clock generator, a digital computer synthesizer, a second frequency divider, phase discriminator; a series-connected voltage-controlled oscillator, a first frequency divider, a phase discriminator, the output of which is connected to the first voltage-controlled generator control input, and the output of the latter is a synthesizer output with a V-shaped law of frequency modulation, and new is that a block is connected in series permanent memory, code comparison circuit, reversible counter, digital-to-analog converter, the output of which is connected to the second control input of the generator, scratched voltage; the output of the reverse counter is connected to the second input of the code comparison circuit, the output of the clock generator is connected to the clock input of the reverse counter, and the address input of the permanent memory unit is a digital input of the synthesizer with a V-shaped law of frequency modulation.

The drawing shows a structural diagram of a synthesizer with a V-shaped law of frequency modulation. A synthesizer with a V-shaped law of frequency modulation contains a clock generator 1, a reverse counter 2, a digital-to-analog converter (DAC) 3, a voltage-controlled generator (VCO) 4, a code comparison circuit 5, a read-only memory (ROM) 6, the first frequency divider 7, phase discriminator (PD) 8, second frequency divider 9, digital computer synthesizer (DAC) 10.

The frequency synthesizer works as follows. The address A of the ROM 6 receives the code A _i , which in the code comparison circuit 5 is compared with the Q code at the output of the reverse counter 2 and if Q <A _i , then the counter 2 switches to the counter mode for increasing. The Q code from the output of counter 2 is supplied to the DAC 3, the voltage from the output of which is supplied to the second control input of the VCO 4. An increase in the Q code leads to an increase in the voltage to the DAC 3, which leads to an increase in the frequency of the VCO of the synthesized signal. The clock generator 1 serves to clock the digital computer synthesizer 10 and the reversible counter 2. The signal from the output of the VCO 4 passes through the first frequency divider 7 and is fed to the first input of the phase discriminator 8, the other input of which is supplied with the signal from the digital computer synthesizer 10 through the second divider frequency 9. At the output of the phase discriminator 8, a control voltage proportional to the error signal will be generated, which is fed to the first control input of the VCO 4. Next, to the address input of the ROM 6, the code B _{j is} received, which determines the value of the final frequency of the synthesizer, which is input to the code comparison circuit 5. Under the condition Q> B _j , the counting mode of the reverse counter 2 is switched to decrease. In accordance with this, a control voltage is generated at the output of the DAC 3, which will determine the frequency of the VCO 4.

At the output of the VCO 4, the frequency of the synthesized signal f _VCO will be proportional to the code Q of the reverse counter 2. The frequency at the output of the VCO is determined by the following formula:

Next, the Q code at the output of counter 2 will begin to decrease until the condition Q <A _{i is} fulfilled, after which the counter direction of counter 2 will again become positive. Thus, at the output of the synthesizer with a V-shaped law of frequency modulation, a frequency-modulated signal is formed, the amplitude of which varies according to the formula:

where f 'is the rate of change of frequency;

f _VCO is the initial frequency of the VCO.

Literature

1. Patent No. 2204197 of the Russian Federation, IPC H03L 7/18, Digital synthesizer of frequency-modulated signals. / Ryabov I.V., Ryabov V.I. - Declared. 04/06/2001. Publ. 05/10/2003. Bull. No. 13.

2. Patent No. 2294054 of the Russian Federation, IPC H03L 7/18, Digital Computing Synthesizer with Quadrature Outputs. / Ryabov I.V. - Declared. 10/25/2005. Publ. 02/20/2007. Bull. No. 5.

3. Ryabov I.V. Digital synthesis of precision signals. Monograph / I.V. Ryabov: Yoshkar-Ola: MarSTU, 2005.152 s.

4. The formation of precision frequencies and signals: Textbook. allowance / N.P. Yampurin, V.V. Boloznev, E.V. Safonova, E. B. Zhalnin; N. Novgorod: Nizhny Novgorod. state tech. Univ., 2003.

Claims (1)

A synthesizer with a V-shaped law of frequency modulation, containing a series-connected clock generator, a digital computer synthesizer, a second frequency divider, the first input of a phase discriminator; a voltage-controlled alternator connected in series, a first frequency divider, a second phase discriminator input, the output of which is connected to a voltage-controlled oscillator first input, and the output of the latter is a synthesizer output with a V-shaped frequency modulation law, characterized in that the unit is connected in series permanent memory, code comparison circuit, reversible counter, digital-to-analog converter, the output of which is connected to the second control input of the generator, governed by stress; the output of the reverse counter is connected to the second input of the code comparison circuit, the output of the clock generator is connected to the clock input of the reverse counter, and the address input of the permanent memory unit is a digital input of the synthesizer with a V-shaped law of frequency modulation.