152
7 Non-coherent and Pseudo-coherent Radar Systems
Fig. 7.2 PCRS functional chart. AA—antenna assembly (unit); ASCU—antenna stabilization and
control unit; CTrm.—coherent transmitter; Circ.—circulator; TRL—TR limiter/spark-gap receiver;
GCU—gain control unit; Att.—attenuator; Mx—mixers; Htd.—heterodyne; AFC—automatic
frequency control unit; IFA—intermediate-frequency amplifier; IFPA—intermediate-frequency
pre-amplifier; TRU—transmit/receiver unit; TDU—turbulence and “wind shear” detection unit;
Synch.—synchronizing unit; MFD—multi-function display
transmitter/receiver (transceiver) is to form non-coherent sequence of radio pulses
and receiving of reflected from target signals, ensuring of coherent processing for
information transmission on hazardous meteorological phenomenon to display unit.
Display unit is intended for visual information representation, and it also provides
an operation synchronization of all radar components.
The transceiver has the following main components:
Superheterodyne type receiver with single frequency conversion is provided by a
mixer 1 and heterodyne. Heterodyne frequency is adjusted in frequency of radiating
sounding signal by AFC unit. The IFPA and main IFA are used in receiver. The last
has a logarithmic-magnitude characteristic with linear initial section. Intermediatefrequency pre-amplifier is intended for amplification of reflected signals coming to
its input with a possibility of gain factor change, since a radar signal is characterized
by broad dynamic range.
Circulator is designed for antenna switching from receiving into transmitting
channel. Reflected from radar target signals (microwave pulses), received by radar
antenna assembly unit, are coming via waveguide duct through circulator, attenuator
to the second mixer. AFC unit circuit serves for maintaining of constant frequency
difference of magnetron and heterodyne (intermediate frequency) due to low stability
of magnetron. Considering that intermediate frequency of radar should be constant
and magnetron oscillator is a frequency-sensitive unit (admitting frequency offset
7 Non-coherent and Pseudo-coherent Radar Systems
Fig. 7.2 PCRS functional chart. AA—antenna assembly (unit); ASCU—antenna stabilization and
control unit; CTrm.—coherent transmitter; Circ.—circulator; TRL—TR limiter/spark-gap receiver;
GCU—gain control unit; Att.—attenuator; Mx—mixers; Htd.—heterodyne; AFC—automatic
frequency control unit; IFA—intermediate-frequency amplifier; IFPA—intermediate-frequency
pre-amplifier; TRU—transmit/receiver unit; TDU—turbulence and “wind shear” detection unit;
Synch.—synchronizing unit; MFD—multi-function display
transmitter/receiver (transceiver) is to form non-coherent sequence of radio pulses
and receiving of reflected from target signals, ensuring of coherent processing for
information transmission on hazardous meteorological phenomenon to display unit.
Display unit is intended for visual information representation, and it also provides
an operation synchronization of all radar components.
The transceiver has the following main components:
Superheterodyne type receiver with single frequency conversion is provided by a
mixer 1 and heterodyne. Heterodyne frequency is adjusted in frequency of radiating
sounding signal by AFC unit. The IFPA and main IFA are used in receiver. The last
has a logarithmic-magnitude characteristic with linear initial section. Intermediatefrequency pre-amplifier is intended for amplification of reflected signals coming to
its input with a possibility of gain factor change, since a radar signal is characterized
by broad dynamic range.
Circulator is designed for antenna switching from receiving into transmitting
channel. Reflected from radar target signals (microwave pulses), received by radar
antenna assembly unit, are coming via waveguide duct through circulator, attenuator
to the second mixer. AFC unit circuit serves for maintaining of constant frequency
difference of magnetron and heterodyne (intermediate frequency) due to low stability
of magnetron. Considering that intermediate frequency of radar should be constant
and magnetron oscillator is a frequency-sensitive unit (admitting frequency offset