SU1695488A1 - Frequency synthesizer - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to simplify the frequency synthesizer while maintaining the grid pitch and switching speed. The frequency synthesizer contains a reference oscillator 1, n decades 2i, 22 ..., 2n, n mixers 3i, Za, ..., 3n, n band-pass filters 4i, 42, ..., 4n, n frequency dividers 5i, 525n, driver 6 control signals. In each of the decades 2i, 222P, the frequency dividers 5i, 52, ..., 5n are made as frequency dividers with a variable division factor. Although this leads to irregularity of the frequency grid pitch, as the number of decades 2i, 22, ..., 2n increases, the number of operating frequencies increases and all these frequencies lie within the passband of the 41.424P bandpass filters, which are the same. 1 il.

Description

, 1 4 --- |

1- Ч7 4ЛТ1- Pcs ЧТНЧТ

3

J

I

Ih

tl

2l

o you

J

00 00

The invention relates to radio engineering and can be used in measuring generators and in exciters of radio transmitting devices.

The aim of the invention is to simplify the frequency synthesizer while maintaining the grid pitch and switching speed.

The drawing shows an electrical structural diagram of a frequency synthesizer.

Frequency synthesizer contains reference oscillator 1, 2 decade 2i, 222n, n mixers 3i, 323n, n bandpass filters

4i, 424n, n frequency dividers 5i, 525П,

shaper 6 control signals.

The frequency synthesizer works as follows.

The reference generator 1 generates a harmonic signal with a frequency f0, which is fed to the first input of the mixers.

3i, 32, ..., 3n, each of n decades 2i, 222P and

the frequency divider 5i of the first decade 2i, the output of which is fed to the second input of the mixer 3i of the same decade 2i.

The band-pass filter 4i of the first decade 2 selects the sum frequency signal.

f 1 fo +

fo

F

where NI is the frequency division factor in the divider 5i of the first decade 2i.

This signal is fed to the input of the frequency divider 52 of the second decade 22. In the mixer 32 of the second decade 22, the signals are combined with the frequency f0 from the generator 1 of the supports1 where the N2 frequency and with the frequency

N2

the division ratio of the divider 52 of the second decade 2. The frequency of the output signal of the second decade is equal to

fo

XЈ L ° L

t out.2 That + tt- +

N2 NI N2

The frequency dividers 5i, 52, ..., 5n are made in the form of frequency dividers with a variable division factor, the control codes to which are supplied from the driver 6.

The use of frequency dividers with a variable division factor in decades 2i, 22, ..., 2n really leads to unevenness of the frequency grid of the synthesizer. In general, the output frequency

The signal of the synthesizer at n decades 2i, 22, ..., 2n is determined by the expression

+ ...

0

five

0

five

0

five

0

five

0

five

Nn Nn-iN2Ni

where f0 is the frequency of the reference oscillator;

Ni ... Nn is the division factor of the dividers 5i, 52, ... 5n in the corresponding decade.

With an increase in the number of decades 2i, 22, ..., 2n, the number of operating points in a given operating frequency band increases, while the irregularity of the frequency grid step also increases. However, all new operating frequencies lie within the bandwidth of the bandpass filters 4i, 42, ..., 4n in the decades 2i, 22, ... 2n, which are the same. Thus, an increase in the number of decades does not necessitate the use of switchable filters.

Thus, simplifying the device while maintaining the frequency grid step and speed is achieved by performing frequency dividers 61.625n in the form of frequency dividers with a variable division factor.

Claims (1)

Invention Formula A frequency synthesizer containing a reference oscillator, a driver of control signals, n series-connected decades, each of which is made up of a series-connected mixer and band-pass filter and frequency dividers, the first input of the mixer each of the decades being the reference input -decade, different in that. that, in order to simplify the frequency synthesizer while maintaining the grid step and switching speed, in each of the decades the frequency divider is designed as a frequency divider with a variable division factor, the signal input of which is the input of the decade, the output of the bandpass filter is the output of the decade, output and control The frequency divider input is connected respectively to the second mixer input and to the corresponding output of the control signal generator, the first decade input and the reference input of each of the n decades are connected to the reference generator output torus.