RFbeam Microwave GmbH

RSP1 Radar Processor

Datasheet

Single channel sensors produce same signal on left and right plane of the complex FFT.

Fig. 9: Single channel signal appears symmetrically in the left and right half

6.3 Interference Filter

Typical interferences appear symmetrically on the left and right plane in the FFT output. Typical noise

source are electronic ballasts and fluorescent lights.

Therefore those interference signals may easily be distinguished from I/Q Doppler signals produced by

stereo sensor modules:

RSP1 adapts threshold (red line) for noise, but not for real I/Q Doppler signals. See also chapter

6.1 Adaptive noise detection

Interferences like in Fig. 10 look different from I/Q Doppler signals caused by movement.

With single channel modules, Doppler signals (Fig. 9) look similar to interferences.

6.4 Random Noise Filter

RSP1 offers different mechanisms in order to suppress influence of stochastic noise:

Random noise produces stochastically distributed peaks in the FFT output and can be reduced by

averaging. FFT averaging can be enabled by parameter S02.

Noise peaks exceeding trigger threshold are counted and must exceed a counter threshold adjusted by

parameter A03.

6.5 Selective FFT Filter

Up to 8 single frequencies may be suppressed by means of array parameters X20 to X27.

Each value represents an FFT bin, that will be masked out from triggering.

Example:

Mask out frequencies 100Hz and 1kHz at sampling rate 2560Hz (Param S02 = 02).

Set parameter X20=000A and param X21=03E8. For more details see chapter FFT Filter

© RFbeam Microwave GmbH www.rfbeam.ch

December 11, 2015

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Fig. 10: I/Q Doppler signal at +44; interference produces 2 peaks on 100 and -100

I/Q Doppler signal

interference