Vaisala RVP900 - Table 4 Real-Time Signal Corrections to I;Q Samples

Table 4 Real-time Signal Corrections to I/Q Samples
Correction Description
Amplitude correction RVP900 computes a running average of the transmit pulse power in the
magnetron burst channel in real-time.
Individual received I/Q samples are corrected for pulse-to-pulse deviations from
this average.
This can substantially improve the phase stability of a magnetron system to
improve the clutter cancellation performance to near klystron levels.
Phase correction The phase of the transmit waveform is measured for each pulse (either the burst
pulse for magnetron systems or the Tx waveform for coherent systems).
The I/Q values are adjusted for the measured phase.
The coherency achievable is better than 0.1° by this technique.
Large signal linearization When an IF signal saturates, there is still considerable information in the signal
since only the peaks are clipped.
The proprietary large signal linearization algorithm used in RVP900 provides an
extra 3 ... 4 dB of dynamic range by accounting for the eects of saturation. This
is possible because an overdriven IF waveform spends some of its time in the
valid range of the converter, and it is possible to deduce information about the
signal.
The configuration and test utilities can run either locally or remotely over the network.
Advantages
• Achieve a wide linear dynamic range (for example, >95 dB depending on pulse width),
without using AGC circuits, which are complex to build, calibrate, and maintain
• Dual or multiple IF multiplexing
• Improved remote monitoring down to the IF level
• Lower initial cost by eliminating most IF receiver components
• Lower life-cycle cost due to reduced maintenance
• Programmable band pass
filter
• Selectable IF frequency
• Software-controlled AFC with automatic alignment
• Software-controlled modules can be adapted to many radars and operational
requirements.
3.1.3.1 Dual Frequency Receive Options
RVP900 IF Digital Receiver (IFDR) performs 38.4 billion multiply accumulate cycles per
second.
Parallel finite impulse response (FIR) filter processing blocks permit the deployment of
simultaneous dual frequency receive strategies.
The digitally synthesized transmitter function allows for processing techniques still in the
research realm for weather radar applications, such as alternating dual frequency staggered
PRTs and pulse compression with
o-frequency short pulses to fill in the near range data.
RVP900 User Guide M211322EN-J
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