Arrangement in a radar system for correction of phase and amplitude errors in a video signal
First Claim
1. In the receiver of a coherent radar system, apparatus for generating from an input signal two signals in quadrature which are phase and amplitude corrected comprising:
- first and second channels, said channels including quadrature detector means receiving the input signal and analog-digital converting means, having outputs, for converting the output of the quadrature detector means to digital values;
a correction means having first and second digital value inputs connected to the outputs of said analog digital converting means for receiving the quadrature digital values from said channels, first and second outputs for emitting phase and amplitude corrected quadrature digital values, and first and second modification inputs associated with the two quadrature digital values; and
a regulating means having first and second loops, said first loop including first multiplier means connected to the first and second outputs of said correction means for forming products of the emitted quadrature digital values, a first comparator means for emitting first binary values in accordance with the polarity of the products from said first multiplier means, and a first register means for storing said first binary values in order to form a first modification signal related to phase error, said first modification signal being fed to one of said modification inputs in response to the signal generated by said first comparator means, and said second loop including first difference forming means connected to the first and second outputs of said correction means for forming difference values of the emitted quadrature digital values, a second comparator means for emitting second binary values in accordance with the polarity of the difference values and second register means for storing said secondary binary values to form a second modification signal related to amplitude error, said second modification signal being fed to the other of said modification inputs, and said correction unit carrying out a correction of said quadrature digital value in one channel in dependence on said first and second modification signals whereby said quadrature digital values in said channels become orthogonal.
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Abstract
An arrangement is provided for correcting the phase and amplitude errors occurring in the quadrature detector of a Doppler radar system. A correction unit (KE) is connected to both analogue-digital converters (AD1, AD2) in the I and Q channels to receive a radar signal which has been received by the system antenna and phase-detected in the quadrature detector (FD1, FD2, FS). The output of the correction unit (KE) is connected to a regulating network (RN) for sensing the output signals from the correction unit (KE) and controlling the latter so that the amplitude and phase errors (a'"'"' and θ'"'"') will be zero.
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Citations
6 Claims
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1. In the receiver of a coherent radar system, apparatus for generating from an input signal two signals in quadrature which are phase and amplitude corrected comprising:
- first and second channels, said channels including quadrature detector means receiving the input signal and analog-digital converting means, having outputs, for converting the output of the quadrature detector means to digital values;
a correction means having first and second digital value inputs connected to the outputs of said analog digital converting means for receiving the quadrature digital values from said channels, first and second outputs for emitting phase and amplitude corrected quadrature digital values, and first and second modification inputs associated with the two quadrature digital values; and
a regulating means having first and second loops, said first loop including first multiplier means connected to the first and second outputs of said correction means for forming products of the emitted quadrature digital values, a first comparator means for emitting first binary values in accordance with the polarity of the products from said first multiplier means, and a first register means for storing said first binary values in order to form a first modification signal related to phase error, said first modification signal being fed to one of said modification inputs in response to the signal generated by said first comparator means, and said second loop including first difference forming means connected to the first and second outputs of said correction means for forming difference values of the emitted quadrature digital values, a second comparator means for emitting second binary values in accordance with the polarity of the difference values and second register means for storing said secondary binary values to form a second modification signal related to amplitude error, said second modification signal being fed to the other of said modification inputs, and said correction unit carrying out a correction of said quadrature digital value in one channel in dependence on said first and second modification signals whereby said quadrature digital values in said channels become orthogonal. - View Dependent Claims (2, 3, 4, 5, 6)
- first and second channels, said channels including quadrature detector means receiving the input signal and analog-digital converting means, having outputs, for converting the output of the quadrature detector means to digital values;
Specification