CN115372916A - Amplitude-phase consistency test method for orthogonal vector synthesis channel intermediate frequency receiver - Google Patents
Amplitude-phase consistency test method for orthogonal vector synthesis channel intermediate frequency receiver Download PDFInfo
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Abstract
The invention discloses a method for testing amplitude-phase consistency of an intermediate frequency receiver of an orthogonal vector synthesis channel, which comprises the following steps: s1, deducing an intermediate frequency signal output formula of an intermediate frequency receiver according to an input signal of an orthogonal vector synthesis channel intermediate frequency receiver, and establishing a signal model; s2, normalizing and demodulating the signals after channel combination in the intermediate frequency receiver, and outputting the signals into two direct current voltage signals carrying target space position information; s3, the direct current signals after the two paths of normalized direct current voltage signals are subjected to detection amplification and output are defined as two angle channel output voltages; testing the output voltages of the two angle channels by adopting an angle channel output voltage testing method; and S4, testing the azimuth characteristics of the two angle channels by adopting an azimuth characteristic testing method on the basis of completing the consistency adjustment of the amplitude and the phase of the three-way signal of the intermediate frequency receiver. The invention can effectively detect the amplitude-phase consistency of the intermediate frequency receiver of the orthogonal vector synthesis channel.
Description
Technical Field
The invention belongs to the technical field of avionics, and particularly relates to a method for testing amplitude-phase consistency of an intermediate frequency receiver of an orthogonal vector synthesis channel.
Background
With the rapid development of modern high-technology equipment, higher requirements are put forward on the missile guidance technology. The seeker is a core component of the precision guided weapon and is used for completing the reservation, automatic search, identification and tracking of a target. An orthogonal vector synthesis channel intermediate frequency receiver (hereinafter referred to as AK intermediate frequency receiver) loaded on a seeker adopts a phase sum difference monopulse angle measurement system, and obtains an azimuth angle and a pitch angle of a target in space by performing sum and difference operation on 4 sub-beams on an antenna. In the two-dimensional angle measuring system, sum channel signals, pitch signals and azimuth signals generated by sum and difference operation are amplified and filtered in respective channels, and the system performs normalization processing and sum and difference phase comparison on the sum and difference channel signals to realize two-dimensional angle measurement. The complete machine design scheme of the AK intermediate frequency receiver adopts a typical superheterodyne technology, and after the input first intermediate frequency signal is subjected to down-conversion twice, three signals of sigma, delta 1 and delta 2 are merged and normalized into two paths of delta 1/sigma and delta 2/sigma signals by using an indirect frequency modulation technology (a channel merging scheme of orthogonal vector synthesis). For a radar receiver adopting a channel combination technology, the phase imbalance and amplitude imbalance of the sum channel and the difference channel before channel combination have great influence on an output signal, and the problem of accurate test is also solved. The research shows that: the amplitude and the relative phase difference of the sum and difference channels inevitably cause the angle measurement error; therefore, the amplitude and phase consistency test before channel merging is very important.
In the prior art, the amplitude and phase test adopts a gain phase meter or a vector network test. A paper "a method for testing receiver amplitude-phase characteristics by using vector network" in paper 34, 3 rd of electronic measurement technology published in 3 rd of 2009 discloses a detection method, which is characterized in that a vector network is used for imitating the frequency conversion times of a receiver to be tested, a related mixer and a related filter are selected, an external reference receiver and a calibration receiver are built, and calibration is completed within the working frequency of the receiver to be tested; and then testing the amplitude and phase parameters of different receiving channels by using the same calibration data. The method has the disadvantages of complex test, extremely complex test steps, long test time, expensive test instrument and high test cost, and a calibration reference receiver and a calibration receiver need to be set up before each measurement.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide a method for testing amplitude-phase consistency of an intermediate frequency receiver in an orthogonal vector synthesis channel.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for testing the amplitude-phase consistency of an orthogonal vector synthesis channel intermediate frequency receiver comprises the following steps:
s1, deducing an intermediate frequency signal output formula of an intermediate frequency receiver according to an input signal of an orthogonal vector synthesis channel intermediate frequency receiver, and establishing a signal model;
the specific process of establishing the signal model is as follows: the received signals of two sub-beams of the phase comparison monopulse antenna are respectively:
in the formula: k represents a fixed coefficient and an amplitude coefficient of an echo signal; theta represents an included angle between the incoming direction of the target echo signal and the axial direction of the equal-strength signal; f. of 0 Representing the frequency of the radio frequency signal; d represents a sub-beam interval; λ represents the radio frequency signal wavelength; theta.theta. 0 Representing the target's off-angle to the antenna axis;
if the amplitude imbalance coefficient of the microwave channel is g and the relative phase difference is phi, the sum channel signal s input to the intermediate frequency receiver of the orthogonal vector synthesis channel Σ(t,θ) Differential channel signal s Δ(t,θ) Comprises the following steps:
in the formula:
representing a phase difference of the reception antenna signals due to the path difference;
the sum channel signal s in formula (3) under the premise of ignoring amplitude-phase inconsistency existing in input signals of the intermediate frequency receiver Σ(t,θ) Differential channel signal s Δ(t,θ) After normalization treatment, the following steps are respectively carried out:
the output signal of the phase comparator is:
in the formula: k is P Representing the receiver and difference channel amplitude imbalance coefficients; k is Δ Representation and channel amplitude coefficients; k Σ Representing a difference channel amplitude coefficient;
assuming that the amplitude and phase of the microwave channel are balanced, i.e. g =1 and Φ =0, the output signal of the phase comparator is:
when phi is Δ ＝φ Σ And theta 0 Very small, sin θ 0 ≈θ 0 ，
The formula is the same as the analysis result of a single-pulse phase comparison angle measurement system;
if the amplitude-phase inconsistency of the intermediate frequency receiver is also taken into account, equation (6) is transformed into:
in the formula: p represents the intermediate frequency receiver and the difference channel amplitude imbalance coefficient; phi is a unit of Δ Representing the intermediate frequency receiver difference channel phase shift; phi is a Σ Representing the intermediate frequency receiver and channel phase shift;
when the channel amplitudes are uniform, i.e. g =1, p =1, equation (8) transforms to:
will be provided with
Approximating with a first order taylor series, we obtain:
according to the formula (10), the phase is not uniformly adjusted by controlling the gain of the error angle voltage output; the relative phase difference between the phase shift voltage compensation and the channel and the difference channel of the seeker computer is adjusted; when the relative phase difference of the sum channel and the difference channel is zero, the change rule of the amplitude of the angle output signal along with the sum signal and the amplitude of the difference signal is checked;
s2, normalizing and demodulating the signals after channel combination in the intermediate frequency receiver, outputting two direct current voltage signals carrying target space position information, namely delta 1/sigma and delta 2/sigma respectively, wherein the ratio of the amplitude of the signals to the amplitude value before channel combination is in direct proportion, and the ratio reflects the size of the angle of the target deviating from the axis of the antenna of the seeker; the polarities of the direct-current voltage signal delta 1/sigma and the direct-current voltage signal delta 2/sigma reflect that compared with a reference signal phase, a normalized signal phase shows that a target deviates from the axis direction of the seeker antenna;
s3, detecting and amplifying the two paths of normalized direct-current voltage signals delta 1/sigma and the direct-current voltage signals delta 2/sigma to output direct-current signals, and defining the direct-current signals as delta 1 and delta 2 angle channel output voltages; the method for testing the output voltage of the channels at the angles of delta 1 and delta 2 by adopting the method for testing the output voltage of the channels at the angles comprises the following steps: the same-frequency and same-amplitude sinusoidal signals output by the same signal source are used for the sum input signal and the difference input signal, the attenuation amounts of the attenuators of the sum channel and the difference channel are set to be 0dB, the amplitude control voltage of the seeker is set to be 0V, the computer phase-shift control voltage of the seeker is adjusted, and the D.C. voltage is output by detecting angles of delta 1 and delta 2;
s4, on the basis of completing consistency adjustment of the amplitudes and phases of the sigma, delta 1 and delta 2 three-way signals of the intermediate frequency receiver, testing the azimuth characteristics of delta 1 and delta 2 angle channels by adopting an azimuth characteristic testing method, wherein the method comprises the following steps of: the amplitudes of three input signals of the intermediate frequency receiver are consistent, and the amplitude unbalance degree of the sum signal and the difference signal is ensured to be within +/-0.5 dB; after amplitude and phase consistency adjustment is finished, keeping the amplitude of the sigma-path signal unchanged, changing the power of the delta 1 and delta 2 input signals in a certain step, and detecting the change of the delta 1 and delta 2 angle channel output voltage along with the input signals.
A system for testing amplitude-phase consistency of an intermediate frequency receiver of an orthogonal vector synthesis channel comprises:
the signal source is used for generating a reference signal;
the one-to-three power divider is connected with the output end of the signal source, takes the reference signal of the signal source as input, and equally divides the reference signal into two paths of same signals to be output;
the first attenuator and the second attenuator are connected with the output end of the one-to-three power divider, respectively receive two paths of signals output by the one-to-three power divider, and adjust and output the power of the signals;
the intermediate frequency receiver is used for receiving signals output by the one-to-three power divider, the first attenuator and the second attenuator, normalizing and demodulating the signals and outputting two direct current voltage signals carrying target space position information; the device is used for receiving two paths of continuously adjustable direct current phase-shifting control voltage and amplitude control voltage output by a seeker computer;
the second local oscillation source and the third local oscillation source are used for inputting a second local oscillation signal and a third local oscillation signal for the intermediate frequency receiver;
and the output end of the intermediate frequency receiver is connected with the digital multimeter.
Due to the adoption of the technical scheme, the invention has the following advantages:
the method for testing the amplitude-phase consistency of the orthogonal vector synthesis channel intermediate frequency receiver is simple to operate, low in cost, quick in detection and suitable for a production line mode, deduces the law that the output signal of the receiver is inconsistent with the amplitude and inconsistent with the phase by establishing a signal receiving model of the receiver, applies an indirect testing method, effectively detects the amplitude-phase consistency of the orthogonal vector synthesis channel intermediate frequency receiver under the condition that the hardware cost of equipment is not increased and the testing efficiency is improved, and has a high application value in a production line.
Drawings
FIG. 1 is a schematic block diagram of the testing of Δ 1 and Δ 2 angle channel output voltage and azimuth characteristics in the present invention.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and examples.
As shown in fig. 1, a system for testing amplitude-phase consistency of an intermediate frequency receiver in an orthogonal vector synthesis channel includes:
the signal source is used for generating a reference signal;
the one-to-three power divider is connected with the output end of the signal source, takes the reference signal of the signal source as input, and equally divides the reference signal into two paths of same signals to be output;
the first attenuator and the second attenuator are connected with the output end of the one-to-three power divider, respectively receive two paths of signals output by the one-to-three power divider, adjust the power of the signals and then output the signals;
the intermediate frequency receiver is used for receiving signals output by the one-to-three power divider, the first attenuator and the second attenuator, normalizing and demodulating the signals and outputting two direct-current voltage signals carrying target space position information; two-way sequential output of signal processor for receiving seeker adjustable direct current phase shift control voltage and amplitude control voltage;
the second local oscillator source and the third local oscillator source are used for inputting a second local oscillator signal and a third local oscillator signal to the intermediate frequency receiver;
and the output end of the intermediate frequency receiver is connected with the digital multimeter.
A method for testing the amplitude-phase consistency of an orthogonal vector synthesis channel intermediate frequency receiver comprises the following specific steps:
s1, supplying power to an intermediate frequency receiver, and inputting a second local oscillation signal and a third local oscillation signal to the intermediate frequency receiver through a second local oscillation and a third local oscillation;
s2, inputting a signal source signal into the power divider, dividing the signal into three paths of same-amplitude and same-frequency signals, and inputting the three paths of same-amplitude and same-frequency signals into sigma, delta 1 and delta 2 of the intermediate frequency receiver;
s3, inputting two paths of continuously adjustable direct current phase-shift control voltage and amplitude control voltage to the intermediate frequency receiver, and setting the voltage to be 0V;
s4, adjusting two paths of computer phase-shift control voltages until the direct-current voltage output by the angle of the intermediate-frequency receiver is the maximum value, and indicating that the three paths of signals of sigma, delta 1 and delta 2 of the intermediate-frequency receiver have the same frequency, the same amplitude and the same phase;
s5, adjusting attenuation amounts of the delta 1 and delta 2 channel attenuation units, attenuating by 6dB each time, and detecting output voltages of delta 1 and delta 2 angle channels after each attenuation; because the output voltage of the angle channel is reduced by half each time when the attenuation unit attenuates signals delta 1 and delta 2 by 6dB, the angle output voltage, namely the DC voltage after synchronous detection of delta 1/sigma and delta 2/sigma, is reduced by a half, because the antenna modulation degree delta 1/sigma and delta 2/sigma at the front end of the intermediate frequency receiver are a%, the equal-strength signal line of the signal deviates from the normal direction of the antenna by 1 degree, and because the-3 dB directional diagram width of the antenna is b DEG, the directional diagram widths of b/2 DEG are respectively arranged towards the left and the right relative to the normal of the polarization of the antenna, therefore, b/2 degrees are selected to reversely deduce the maximum modulation degree of delta 1/sigma and delta 2/sigma of the difference channel to be a% multiplied by b/2 degrees =50%, in order to comprehensively check the amplitude-phase consistency of the intermediate frequency receiver in the antenna directional diagram, when the signals of the difference channel are respectively attenuated by 0dB, 12dB, 18dB, 24dB and 30dB, namely when the modulation degrees are respectively 100%, 50%, 25%, 12.5% and 6.25%, the output voltages of the detected angle channels are respectively V1, V2, V3, V4 and V5, and the detected output voltages of the delta 1 and delta 2 angle channels are calculated according to a formula (11), so that the azimuth characteristic slope is obtained;
K＝10×Vi×VΣ÷VΔi (11)
in the formula: k represents the slope of the azimuthal characteristic in mV/%; vi denotes the output voltage of the angle channel in units V; v Σ represents the voltage of the XS1 input signal in units μ V; v Δ i represents the voltage of the XS2 (or XS 3) input signal corresponding to the i-th attenuation, in units of μ V;
the slope of the azimuth characteristic calculated according to the formula (11) is kmV/%, the detected output voltages of the angle channels are all in the range of (k +/-10) mV/%, and the amplitude-phase consistency of the intermediate frequency receiver is qualified.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention, and all equivalent changes and modifications made within the scope of the claims of the present invention should fall within the protection scope of the present invention.
Claims (2)
1. A method for testing amplitude-phase consistency of an orthogonal vector synthesis channel intermediate frequency receiver is characterized by comprising the following steps: which comprises the following steps:
s1, according to an input signal of an orthogonal vector synthesis channel intermediate frequency receiver, deducing an intermediate frequency signal output formula of the intermediate frequency receiver, and establishing a signal model;
the specific process of establishing the signal model is as follows: the received signals of two sub-beams of the antenna of the phase comparison monopulse are respectively as follows:
in the formula: k represents a fixed coefficient and an amplitude coefficient of an echo signal; theta represents an included angle between the incoming direction of the target echo signal and the axial direction of the equal-strength signal; f. of 0 Representing the frequency of the radio frequency signal; d represents a sub-beam interval; λ represents the radio frequency signal wavelength; theta 0 Representing the target's off-angle to the antenna axis;
if the amplitude imbalance coefficient of the microwave channel is g and the relative phase difference is phi, the sum channel signal s input to the orthogonal vector synthesis channel intermediate frequency receiver Σ(t,θ) Differential channel signal s Δ(t,θ) Comprises the following steps:
in the formula:
representing a phase difference of the reception antenna signals due to the wave path difference;
the sum channel signal s in the formula (3) under the premise of neglecting the amplitude-phase inconsistency existing in the input signal of the intermediate frequency receiver Σ(t,θ) Differential channel signal s Δ(t,θ) Is subjected to normalization treatmentThe following are respectively:
the output signal of the phase comparator is:
in the formula: k P Representing the receiver and difference channel amplitude imbalance coefficients; k Δ Representation and channel amplitude coefficients; k Σ Representing a difference channel amplitude coefficient;
assuming that the amplitude and phase of the microwave channel are balanced, i.e. g =1 and Φ =0, the output signal of the phase comparator is:
when phi is Δ ＝φ Σ And theta 0 Very small, sin θ 0 ≈θ 0 ，
The formula is the same as the analysis result of a single-pulse phase comparison angle measurement system;
if the amplitude-phase inconsistency of the intermediate frequency receiver is also considered, equation (6) is transformed into:
in the formula: p denotes an intermediate frequency receiverA sum-difference channel amplitude imbalance coefficient; phi is a unit of Δ Representing the intermediate frequency receiver difference channel phase shift; phi is a unit of Σ Representing the intermediate frequency receiver and channel phase shift;
when the channel amplitudes are uniform, i.e. g =1, p =1, equation (8) transforms to:
will be provided with
By approximation with a first order taylor series, we obtain:
according to the formula (10), the phase is not uniformly adjusted by controlling the gain of the error angle voltage output; the relative phase difference between the phase shift voltage compensation and the channel and the difference channel of the seeker computer is adjusted; when the relative phase difference of the sum channel and the difference channel is zero, the change rule of the amplitude of the angle output signal along with the sum signal and the amplitude of the difference signal is checked;
s2, normalizing and demodulating the signals after channel combination in the intermediate frequency receiver, outputting two direct current voltage signals carrying target space position information, namely delta 1/sigma and delta 2/sigma respectively, wherein the amplitude of the signals is in direct proportion to the amplitude value before channel combination, and the amplitude of the target deviating from the axis angle of the seeker antenna is reflected; the polarities of the direct current voltage signal delta 1/sigma and the direct current voltage signal delta 2/sigma reflect that the normalized signal phase is compared with the reference signal phase and represents the direction of the target deviating from the axis of the antenna of the seeker;
s3, detecting and amplifying the two paths of normalized direct-current voltage signals delta 1/sigma and the direct-current voltage signals delta 2/sigma to output direct-current signals, and defining the direct-current signals as delta 1 and delta 2 angle channel output voltages; the method for testing the output voltage of the angle channels delta 1 and delta 2 is adopted to test the output voltage of the angle channels, and comprises the following steps: the same-frequency and same-amplitude sinusoidal signals output by the same signal source are used for the sum input signal and the difference input signal, the attenuation amounts of attenuators of a sum channel and a difference channel are set to be 0dB, the amplitude control voltage of a seeker is set to be 0V, the computer phase-shift control voltage of the seeker is adjusted, and the D.C. voltage is output at the angles of Delta 1 and Delta 2;
s4, on the basis of completing consistency adjustment of amplitudes and phases of three signals of sigma, delta 1 and delta 2 of the intermediate frequency receiver, testing the azimuth characteristics of delta 1 and delta 2 angle channels by adopting an azimuth characteristic testing method, wherein the method comprises the following steps: the amplitudes of three input signals of the intermediate frequency receiver are consistent, and the amplitude unbalance degree of the sum signal and the difference signal is ensured to be within +/-0.5 dB; after amplitude and phase consistency adjustment is completed, keeping the amplitude of the sigma-path signal unchanged, changing the power of the delta 1 and delta 2 input signals in a certain step, and detecting the change of delta 1 and delta 2 angle channel output voltage along with the input signals.
2. A system for testing amplitude-phase consistency of an orthogonal vector synthesis channel intermediate frequency receiver is characterized in that: it comprises the following steps:
the signal source is used for generating a reference signal;
the one-to-three power divider is connected with the output end of the signal source, takes the reference signal of the signal source as input, and equally divides the reference signal into two paths of same signals to be output;
the first attenuator and the second attenuator are connected with the output end of the one-to-three power divider, respectively receive two paths of signals output by the one-to-three power divider, adjust the power of the signals and then output the signals;
the intermediate frequency receiver is used for receiving signals output by the one-to-three power divider, the first attenuator and the second attenuator, normalizing and demodulating the signals and outputting two direct-current voltage signals carrying target space position information; the device is used for receiving two paths of continuously adjustable direct current phase-shifting control voltage and amplitude control voltage output by a seeker computer;
the second local oscillator source and the third local oscillator source are used for inputting a second local oscillator signal and a third local oscillator signal to the intermediate frequency receiver;
and the output end of the intermediate frequency receiver is connected with a digital multimeter.
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