SU1517113A2 - Digital frequency synthesizer - Google Patents

Abstract

The invention relates to radio engineering and can be used in computing and measuring devices. The purpose of the invention is to expand the range of synthesized frequencies. The device contains a clock Gr.R. 1, a frequency setting block 2, a frequency register 3, a multiplier of 4 codes, an accumulator adder 5, an amplitude calculator 6, a DAC 7, a low-pass filter 8, a counter 9 and a memory block / PSU / 10. To achieve Target between the bit outputs of the counter 9 and the bit inputs of the block 2 are entered by the power supply unit 11. At the output of the device many different sequences of frequencies are obtained. Each of the frequencies F _{out of the} separately considered sequence is determined by the expression F _out = F _t ^. K _i ^. M _j ^. 2 ^-N , where F _t is the frequency of g-1, K _I is the numbers that determine the values of the central output frequency, determined by the content of BP 11, M _J are the detuning factors contained in BP 10, N is the size of the adder 5. The use of PD 11 allows you to enter another variable in the output frequency formula, which leads to an expansion of the range of synthesized frequencies. 1 il.

Description

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The invention relates to radio engineering, can be used in computing and measuring devices, and is an improvement in the image of the author. St. No. 1210198.

The aim of the invention is to expand the range of synthesized frequencies.

The black-and-white model presents a structural electrical circuit of a digital frequency synthesizer.

The digital frequency synthesizer contains a clock generator 1, a frequency setting block (BOOP) 2, a frequency register 3, a multiplier of 4 codes, an accumulator adder 5, a calculator of 6 amplitudes, a digital-analog converter (DAC) 7, a low-pass filter 8, a counter 9, the first block 10 memory, the second block 11 memory.

Digital frequency synthesizer works as follows.

BOOK 2 sets the K values that determine the values of the central output frequencies. The transfer of numbers K in binary code to the accumulating adder 5 through multiplier 4 provides register 3. Multiplier 4 multiplies the number K by the detuning amount code stored in the first memory block 10, the capacity of which depends on the detuning value. Based on the current phase data, the calculator 6 counts the digital values of the modulus of the current amplitude, and the amplitude sign from the output of accumulating adder 5 goes directly to the sign input of the DAC 7 and to the input of the counter 9, which counts the number of periods of the synthesized sinusoidal signal and ensures the change of detuning factors and the numbers defining the central output frequencies,

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5 о 5 0 5

the values of which are contained respectively in the first 10 and second 11 memory blocks. A DAC 7 converts discrete amplitude values into a stepwise analog signal, the first harmonic of which is extracted using filter 8. As clock signals, signals from the outgrowth of clock generator 1 are used.

The output of the digital frequency synthesizer produces a multitude of different frequency sequences. Each of the frequencies fg |, i, f of the separately considered sequence is determined by the expression

f in., - M 2. where f is the frequency of the clock generator of the I generator;

To - the numbers that determine the values of the center output frequency, and are determined by the contents of the second memory block 11;

M. - detuning factors contained in the first memory block 10; N is the size of accumulator adder 5.

The center frequency is determined by

f f. V, -J

1 4-1 t

The use of the second memory block I1 allows one more variable to be entered into the output frequency formula, which leads to an expansion of the range of synthesized frequencies.

Claims (1)

Invention Formula Digital synthesizer frequency auth. St. No. 1210198, characterized in that, in order to expand the range of synthesized frequencies, a second memory block is inserted between the bit outputs of the counter and the bit inputs of the frequency setting unit.