SU389607A1 - DEVICE FOR OBTAINING DISCRETE FREQUENCIES - Google Patents

Description

one

The invention relates to radio devices used in the communication technology and measurement technology. It can be applied in equipment for frequency comparison, in discrete information transmission systems, and frequency synthesizers.

Devices for obtaining discrete frequencies are known, comprising a trigger generator connected to one modulator input via serially connected frequency divider and harmonic generator, and to another modulator input via serially connected second frequency divider and frequency multiplier, and a set of bandpass filters, connected to the modulator output.

However, in the case of working with a single reference oscillator, such devices only allow receiving even or odd frequencies. To obtain the entire frequency grid at a given interval, it is necessary to use at least two devices that form two independent frequency grids shifted; but frequency relative to each other by the interval value. Since the signals modulated by the spectrum from the output of reHepaiTopa harmonics must have different frequencies, the overall circuitry of the devices is quite complex.

The purpose of the invention is to improve the filtering of the useful signal.

The proposed device is characterized in that it is equipped with an additional set of bandpass filters connected to the second output of the harmonic generator.

The drawing shows a block diagram of a device for obtaining discrete frequencies.

The device consists of a reference oscillator /, two frequency dividers 2 and 3, a frequency multiplier 4, a harmonic generator 5, a modulator 6, and four band-pass filters 7-10. Each filter has its own tuning frequency, and the 7 to 9 filters connected to the modulator output are tuned to odd frequencies, and the filters 8 and 10 connected to the harmonic generator, to even frequencies. The filtered signals are removed from the outputs 11-14 of the respective filters.

In the frequency divider, the 3 frequency of the reference oscillator / is reduced to a value equal to twice the interval between the output frequencies, and then the harmonic generator 5 generates 1 Of the output signal of the divider 3 with a series of short pulses with a uniform discrete spectrum. Since the pulse frequency is twice as high as the required interval, this spectrum contains only even frequencies that are allocated by narrowband filters 8 and 10. Besides the even frequency filters, the pulses from the harmonics generator 5 are given to modulator 6, in which they modulate the output signal of frequency multiplier 4. The frequency division factor of the reference oscillator 1 in divider 2 is selected so that it multiplies it by an odd number of times Hai modulator input 6 postunal is an odd frequency. As a result, at the output of the modulator, a diacret spectra is obtained, containing only odd frequencies. The individual components of this spectrum are separated by band-pass filters 7 VL 9. Thus, using two chains of filters included at: the output of the harmonic generator and the modulator, both even and odd frequencies are obtained.

Subject invention

An apparatus for obtaining discrete frequencies comprising a reference oscillator connected to one modulator input via serially connected frequency divider and harmonic generator, and to another modulator input via serially connected second frequency divider and multiplier

frequency, and a set of bandpass filters connected to the modulator output, characterized in that, in order to improve the filtering of the useful signal, it is equipped with an additional set of bandpass filters connected to the second output of the harmonic generator.

i3

12

- / -