RU2754793C1 - Device for selection and frequency conversion of modulated radio signals - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: device relates to radio engineering and can be used in radio receiving devices and measuring equipment. The device consists of two-wire line (TWL) (1), the input of which is supplied with a modulated radio signal U_s (_g, _s), a two-wire line (TWL) (2), the input of which is supplied with a signal from the modulated oscillator U_g(ω_g, Ω_g). (TWL) (1), (TWL) (2) they are separately loaded on a resistance R equal to the wave resistance of the line, and they are oriented counter-oriented in the direction of the waves running in them. Between the wires (TWL) (1), (TWL) (2), a conductor (C) (3) is placed parallel to them, which is connected to a bandpass filter (BF) (4) tuned to the modulation frequency Ωg of the oscillator oscillations. In this case, the length (TWL) (1), (TWL) (2) and the length (C) (3) are selected at least one tenth of the wavelength of the modulated radio signal.

EFFECT: provided is possibility of selection and frequency conversation of radio signals of different types of modulation in one device without side conversation channels.

1 cl, 1 dwg

Description

The invention relates to radio engineering and can be used in radio receivers and measuring equipment for selection (selectivity) and frequency conversion of modulated radio signals.

Known:

1. Devices for selection and frequency conversion of modulated radio signals, containing semiconductor devices and resonant systems [Davydov Yu.G. and other radio receivers. / Edited by prof. A.P. Zhukovsky - M .: Higher school, 1989, pp. 8-10, 32, 38, 40, 81-82, 85-86, 87-92], which are made in the form of separate nodes, and to change the frequency of the radio receiving device, the resonant systems of the selector and the frequency converter must be reconstructed simultaneously. A characteristic disadvantage of such devices is the appearance of side reception channels: mirror, combinational, intermodulation.

2. Frequency converters [RF patents: No. 2248661 H03D 7/00, No. 2276452 H03D 7/00, No. 2285330 H03D 7/14, No. 2311728 H03D 7/14], which transfer the radio signal from one carrier frequency to another, but do not allow to carry out the selection of radio signals.

3. Demodulator of amplitude-modulated (AM), frequency-modulated (FM), phase-modulated (FM) signals [RF Patent No. 2204195 H03D 5/00], which separates a message from a modulated radio signal, but does not allow selection and frequency conversion, i.e. .e. transfer the spectrum of the radio signal from one carrier frequency to another. The closest to the claimed device in terms of the combination of coinciding essential features is a demodulator of AM, FM, FM signals [RF Patent No. 2204195 H03D 5/00]. - prototype.

The demodulator of AM, FM, FM signals contains a two-wire short-circuited line and a conductor between its wires, parallel to them, of the same length, the ends of which are connected to the input of the low-pass filter.

The purpose of the invention is the selection and frequency conversion of modulated radio signals, i.e. transfer of a modulated signal from one carrier frequency to another, combining the selection and frequency conversion of modulated signals in one device, while eliminating the occurrence of side reception channels. This goal is achieved by the fact that the modulated radio signal is supplied to the input of a two-wire line, between the wires of which, parallel to them, a conductor of the same length is placed, and to select and convert the frequency of modulated radio signals, another two-wire line of the same length is introduced coaxially with it and is connected to its input signal from the generator of modulated oscillations. The carrier frequency of the modulated oscillator is the same as the carrier frequency of the modulated radio signal, and the modulation frequency is higher than the modulation frequency of the radio signal.

The two-wire lines are separately loaded to a resistance equal to the wave impedance of the line, and in the direction of the waves traveling in them are oriented oppositely, and the conductor placed between the wires of the lines, parallel to them, is connected to the input of the band-pass filter tuned to the modulation frequency of the oscillations of the generator. In this case, the length of the two-wire lines and the length of the conductor placed between the wires of the lines, parallel to them, are chosen at least one tenth of the wavelength of the modulated radio signal. From the output of the bandpass filter, a signal with a carrier frequency equal to the modulation frequency of the oscillator oscillations, modulated by a radio signal message, is fed for subsequent amplification and demodulation.

The authors have not identified among the technical solutions known to them for a similar purpose, one that would contain a set of essential features, with the declared distinctive features. This allows the claimed technical solution to be recognized as meeting the "novelty" criterion.

The possibility of implementing the claimed invention is confirmed by the electrical circuit of the device for selecting and converting the frequency of modulated radio signals, the principle of its operation and experimental results.

The device for selecting and converting the frequency of modulated radio signals, shown in the drawing, contains:

1. Two-wire line 1, to the input of which a modulated radio signal U _c (ω _c > Ω _c ) is connected, for example, from an antenna or a broadband antenna amplifier.

2. Two-wire line 2, to the input of which the signal U _g (ω _g > Ω _g ) from the modulated oscillator is connected, the carrier frequency of which coincides with the carrier frequency of the modulated radio signal (ω _g = ω _c ), and the modulation frequency Ω _{g is} greater than the modulation frequency Ω _from radio signal.

3. Two-wire lines 1, 2 are separately loaded on resistance R, equal to the wave impedance of the line, and are oriented oppositely in the direction of the waves traveling in them.

4. Conductor 3, which is located between the wires of two-wire lines 1, 2, parallel to them.

5. Bandpass filter 4, to the input of which conductor 3 is connected. The length of two-wire lines 1, 2 and the length of conductor 3 are chosen at least one tenth of the wavelength of the modulated radio signal.

Bandpass filter 4 is tuned to the modulation frequency Ω _{g of the} oscillator oscillations. From the output of the bandpass filter 4, a signal with a carrier frequency equal to the modulation frequency of the oscillator oscillations, and modulated by a radio signal message, is supplied for subsequent amplification and demodulation.

To describe the principle of operation of the claimed device for selection and frequency conversion of modulated radio signals, the initial relations are:

, действующая на электрон, находящийся в пространственно неоднородном по амплитуде электромагнитном поле [Л.А.Арцимович, Р.З.Сагдеев. Физика плазмы для физиков. - М.: Атомиздат, 1979, с.35]:1. Power of high frequency pressure

acting on an electron located in a spatially inhomogeneous amplitude electromagnetic field [LA Artsimovich, RZ Sagdeev. Plasma physics for physicists. - M .: Atomizdat, 1979, p. 35]:

where e is the electron charge;

m _e is the mass of an electron;

ω is the circular frequency of the electromagnetic field;

∇ - mathematical operation of the gradient;

| E | - the amplitude of the electric field.

2. The square of the amplitude of the resulting electric field of traveling opposite electromagnetic waves of the same frequency [BM Yavorsky, AA Detlaf. Physics Handbook. - M .: Nauka, 1985, p. 291]:

where | Е _c | - the amplitude of the electric field in a two-wire line 1:

- при AM;

- at AM;

- при ЧМ, ФМ,

- at FM, FM,

where U _mc is the voltage amplitude of the carrier oscillation of the radio signal;

d _e - the equivalent distance between the wires of the line;

| E _g | - the amplitude of the electric field in the two-wire line 2:

- при AM,

- at AM,

- при ЧМ, ФМ,

- at FM, FM,

where U _mg is the voltage amplitude of the carrier oscillation of the generator;

ΔΨ is the phase difference of electromagnetic waves traveling towards the opposite direction in two-wire lines 1, 2:

ΔΨ = 2mz - for AM radio signal and AM generator signal;

ΔΨ = 2mz + (M _g cosΩ _g t-M _with cosΩ _c t) - for FM, FM radio signal and FM, FM signal generator;

ΔΨ = 2mz-M _with cosΩ _c t - at FM, FM radio signal and AM generator signal;

m is the wave number of high-frequency oscillations of the radio signal and the generator signal when their frequencies coincide.

Ω _s , Ω _g is the circular frequency of modulation of the radio signal and the generator signal, while Ω _g > Ω _s ;

M _s , M _g is the modulation depth of the radio signal and the generator signal at AM or the modulation index at FM, FM;

z is the current coordinate measured from the input of two-wire line 1.

Based on the above relationships, the principle of operation of the inventive device for selecting and converting the frequency of modulated radio signals is as follows. When high-frequency modulated currents of a traveling wave of a radio signal and a signal from a generator pass through two-wire lines 1, 2, oriented oppositely, in the region of two-wire lines 1, 2, as a result of interference of electromagnetic fields of the same frequency, an electric field that is spatially inhomogeneous in amplitude is formed, the gradient of the square of the amplitude of which for different the types of modulation of the radio signal and oscillations of the generator when their carrier frequencies coincide is:

1. With AM radio signal and AM generator signal

2. With narrowband FM, FM radio signal and narrowband FM, FM signal generator

3.When narrowband FM, FM radio signal and AM signal generator

In conductor 3, placed between the wires of two-wire lines 1, 2, parallel to them, under the influence of the force of high-frequency pressure (1), taking into account (3, 4, 5), there is a current proportional to ∇ | E | ² , the spectral composition of which contains a component with a modulation frequency of the generator Ω _g and two side components with a frequency (Ω _{g -} Ω _s ) and (Ω _g + Ω _s ):

1. With AM radio signal and AM generator signal:

2. With narrowband FM, FM radio signal and narrowband FM, FM generator signal:

3. For narrowband FM, FM radio signal and AM generator signal:

Under the influence of the current (6, 7, 8) at the ends of the conductor 3, a voltage appears that changes in time with the modulation frequency of the oscillations of the generator Ω _g , modulated by the message Ω _{from the} radio signal. This voltage is applied to the input of the band-pass filter 4, which is tuned to the modulation frequency of the oscillations of the generator Ω _g and does not pass to the output of the filter 4 the spectrum component with the message frequency Ω _s , as well as the high-frequency voltage of the radio signal and the generator, partially leaking out in the conductor 3.

The selection of modulated radio signals in the claimed device is carried out by changing the frequency of the generator without changing the modulation frequency Ω _g . When the frequency of the oscillator with the frequency of the modulated RF signal supplied from the antenna in the two-wire line 1, 2 is formed an inhomogeneous amplitude electric field under the influence of which the conductor 3 a voltage with a modulation frequency Ω _g oscillator modulated message Ω _{with the} radio signal. In this case, no combinational components arise in the spectrum of the converted radio signal, and, therefore, when using the inventive device for selecting and converting the frequency of modulated radio signals, side reception channels are not formed, which are characteristic of known devices for similar purposes.

Thus, the selection and frequency conversion of modulated radio signals on lines with distributed parameters is carried out due to the fact that the force of high-frequency pressure on the conduction electrons and the resulting current in conductor 3 with the frequency of modulation of oscillations of the generator, modulated by the message of the radio signal, are proportional to the gradient of the square of the amplitude of the high-frequency modulated spatially inhomogeneous electric field in the area of distributed lines.

Reception of signals from broadcasting stations using the proposed device confirms its performance.

Claims (1)

A device for selecting and converting the frequency of modulated radio signals, containing a filter and a two-wire line, to the input of which a modulated radio signal is connected, and between its wires, parallel to them, a conductor of the same length is placed, which is connected to the filter, while the length of the two-wire line and the conductor is not selected less than one tenth of the wavelength of the modulated signal, characterized in that, coaxially with the two-wire line, to the input of which the modulated radio signal is connected, another two-wire line of the same length is introduced, and a signal from the modulated oscillator is connected to its input, the carrier frequency of which coincides with the carrier frequency modulated radio signal, and the modulation frequency is higher than the modulation frequency of the radio signal, while the two-wire lines are separately loaded to a resistance equal to the wave impedance of the line, and are oriented oppositely in the direction of the waves traveling in them, and the conductor placed between the wires of the two-wire lines, parallel to them, is Connected to the input of a band-pass filter tuned to the modulation frequency of the oscillator oscillations.

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