SU1406782A1 - Digital frequency synthesizer - Google Patents

Abstract

The invention relates to a pulse technique and can be used in frequency grid generation devices. The purpose of the invention — an increase in speed — is achieved by eliminating the effect of delays in the decoder and in the reversible pulse counter. Another goal — enhanced functionality — is achieved by obtaining an additional pulse sequence that is phase-shifted relative to the main one. The drawing shows the reference frequency generator 1, the program block 2, the pulse shaper 3, the phase-shifting chain 4, the phase shift control unit 5, the AND 6-9 elements, the OR 10 element, the decoder 11, the reverse pulse counter 12 pulses, the register 13. The control unit 5 phase shift contains elements AND 14-17 and element OR 18. Input buses 19 and 20 are connected respectively to the output of the element OR 10 and to the output of block 5. Block 2 can be made in the form of a switched switch of a controlled divider or frequency multiplier with a uniform output imp lsnoy sequence. 1 hp f-ly, sp. (L O) 0 hd

Description

The invention relates to a pulse technique and can be used in frequency grid generation devices.

The purpose of the invention is to increase the speed by eliminating the effects of delays in the decoder and in the reversible pulse counter, as well as expanding the functionality by obtaining an additional pulse sequence that is phase-shifted relative to the main one.

The drawing shows the electrical structure of the device.

The digital frequency synthesizer contains a reference frequency generator 1, the output of which is connected to the input of the program block 2 and through the shaper of 3 pulses to the phase shifter input of the chain 4, the outputs of which are connected to the corresponding inputs of the first phase shift control unit 5 and the first the inputs are respectively the first 6, second 7, third 8 and fourth 9 elements AND, the outputs of which are connected to the corresponding inputs of the element OR 10, the decoder 11, the reversible counter of 12 pulses and the register 13, the corresponding outputs which are connected to the second inputs of the first 6, second 7 third 8 and fourth 9 elements And and the corresponding inputs of the second group of inputs of the phase shift control unit 5, the control input with the output of the phase shift control unit 5, information inputs with the corresponding outputs of the decoder 1I The inputs of which are connected to the corresponding outputs of the reversible counter 12 pulses, the clock and control inputs of which are connected respectively to the first and second outputs of the software block 2.

The phase shift control unit 5 contains the first 14, second 5, third 16 and fourth 17 elements, the first inputs of which are connected to the corresponding inputs of the first group of inputs of the phase shift control unit 5, the first, second, third and fourth inputs of the second group of inputs of which are connected to the second inputs, respectively, of the second 15, third 16, fourth 17 and first 14 And elements, the outputs of which are connected to the corresponding inputs of the IL element

five

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0

five

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five

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five

18, the output of which is connected to the output of the phase shift control unit 5.

The first 19 and second 20 output buses are connected respectively to the output of the element OR 10 and to the output of the phase shift control unit 5.

Program block 2 can be implemented as switched switches of a controlled splitter (or multiplier) of a frequency with a uniform output pulse sequence.

Digital frequency synthesizer works as follows.

For simplicity of consideration of the device operation, the drawing shows a phase-shifting chain 4 having four taps, which corresponds to a phase shift between adjacent taps 90 (for the general case, the number of taps of the chain can be any).

From the pulse sequence coming from the output of the generator 1 through the shaper 3, the chain 4 forms four pulse sequences that are shifted relative to each other by 90. In two groups of IB-9n 14-17 elements, the switching of these sequences is performed, and on elements 10 and 18

The switching direction determines the operation of the device to increase or decrease the frequency and is set by the character code from the second output of block 2.

The synchronization is switched from one pulse sequence of chain 4 to another in the device is performed using pulses of an additional pulse sequence generated by block 5, which write to the register 13 of the next state of the decoder I1 at times that exclude the possibility of one pulse or the appearance of spurious pulses on bus 19, since the switching (on bus 20) and switched at the outputs of the chain 4 pulse sequences can not coincide in time.

The switching speed is determined by the specific requirements of the output frequency deviation from the frequency of the oscillator 1 and is set by block 2 using the control of the pulse sequence of the nail fed to the clock input

arbitrary moments

counter 12 in time.

Let us consider in detail the operation of the synthesizer to increase the output frequency.

The counter 12 operates in this case for the subtraction, and the increase in the output frequencies occurs due to the decrease in the pulse period of the output sequences at the moments of switching. The control pulses from register 13 to the inputs of the group of elements I are received in such a way that switching of pulse sequences occurs in the group of elements AND 6-9 in order from the first, from the fourth, from the third and from the second outputs of the chain 4, and in the group of elements 14 - 17 in the sequence, from the second, from the first, from the fourth and from the third outputs of the chain 4; At the same time, on the tires 19 and 20, pulse sequences are formed, shifted relative to each other by 90

confirm the information in the register 13.

Upon receipt of the following pulses from the output of block 5, similar switching is made to further switching of the pulse sequences of chain 4. Thus, the pulse sequences on tires 19 and 20

10 are shifted by 90 relative to each other, and as at the moments of switching the pulse sequences of string 4, the duration of the pulse tracking on buses 19 and 20 decreases, the output frequency will increase.

The operation of the device to reduce the output frequency of the prSychocyte is similar to the work of increasing, with only

2Q by the difference that the switching of the pulse sequences of the chain 4 in the two groups of elements I is carried out in the sequence from the first, from second to fn /.

Output where fg is the frequency of the generator pulses. pa 1;

fp is the switching frequency of the taps of the chain A.

from the third and from the fourth output and from the 25th phases of the chain 4 in the group of elements I

6 - 9 and from the second, from the third, from the fourth and from the first outputs of the chain 4 in the group of elements And 14 - 17, which leads to a decrease in the output frequency of 30 devices1.

Claims (1)

1. A digital frequency synthesizer containing a reference frequency generator, the output of which is connected to the input of the program block and through a pulse shaper to the input of the phase-shifting chain, the first, second, third and fourth outputs of which are connected to the corresponding inputs of the first group of inputs of the phase shift control unit and the first inputs the first, second, third, and fourth elements, respectively, the second inputs of which are connected to the corresponding inputs of the second group of inputs of the phase shift control block; the outputs are with the corresponding inputs of the OR element, the output of which is connected to the first output bus, the decoder, the inputs of which are connected to the corresponding outputs of the reversible pulse counter, characterized in that, in order to improve speed, a second output bus and a register are entered, the outputs of which are connected to the corresponding inputs of the second group of block inputs 514067826 control of phase shift, control, second, third and fourth elec- tive input - with the output of the control unit I copies, the first inputs of which are connected by a phase-shift and from the second output with corresponding inputs of the blank, information inputs - with the corresponding group of inputs of the control unit the output of the decoder, the phase shift, the first, second, three-way clock and control inputs and the fourth inputs of the second group dy of the reverse pulse counter of whose inputs are connected to the second connected respectively with the first inputs of the second, respectively, alarm outputs of the program block. The fourth, fourth, and first element 2, Synthesizer according to claim 1, of the I-and-O types, the outputs of which are through the elements so that the control-OR unit is connected to the output of the phase-shift control unit contains phase-shifting.