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Aug 21, 2013, 02:54 AM
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Zoom H2 radar


Finally hit the Zoom H2 with the radar output. The Zoom H2 uses the TLV320AIC32, the highest quality ADC in the apartment.





A quick comparison revealed no significant difference in the range of interest.


It turns out while the Zoom H2 records 24 bit files, its ADC documentation never specifies how many bits it records. It oversamples at 128x to fill in extra bits. It seems to convert 19 unique bits. There's a 528 sample section at the beginning of every file where only 19 bits are written.


It definitely can receive reflections from materials other than metal, but not in FMCW mode. In doppler mode, the gain can be increased to 1000x, where it detects wood & body parts. The problem with doppler is it can't detect slow movement.


So the problem with detecting non metallic materials is the gain, which is limited by very a large low frequency component in the signal. It would take an unreasonably sharp filter to cut it off.




Also tried sinusoidal frequency modulation, which made even more low frequency offset.

Finally, a video showing how well the radar works, including its inconsistencies.

Radar test 2 (3 min 5 sec)


That was using single pass 256 ksamples/sec 1024 sample windows.
Last edited by Jack Crossfire; Aug 21, 2013 at 04:56 AM.
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