User Guide (Version 2.2) of the
SiRad Simple® Evaluation Kit
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fmin / fmax:
displays the result of the frequency scan (done once automatically during startup) to
find the minimum and maximum supported frequencies of the installed radar frontend (f
min
and f
max
).
The scan can be performed manually by using the ‘fscan’ feature (click it 3 times in a row).
fscan:
performs a manual min / max frequency scan for the installed frontend when clicked 3 times
in a row. The frequencies supported by your frontend should be approximately in the range of
119100 to 125900 MHz for the 122 GHz frontend on the SiRad Simple® sensor.
max BW:
sets the frequency ramp bandwidth to the maximum possible value for the installed
frontend when clicked 3 times in a row. The maximum bandwidth is hardware dependent and may
vary. The maximum useful bandwidth BW is (including a margin of 200 MHz):
BW
max
= (f
max
– 100 MHz) – (f
min
+ 100 MHz).
Frontend:
switches the presets for the used radar frontend.
Only the 122 GHz option is useful for
the SiRad Simple® sensor. The other presets can lead to undefined behavior.
VCO Divider:
is hardware dependent per frontend type.
The VCO divider for the SiRad Simple®
sensor (v2.2) is 64, fixed.
Bandwidth:
set the bandwidth (in MHz) used for the frequency ramps. The bandwidth should not
exceed the maximum frequency f
max
of the frontend minus the minimum frequency f
min
of the
frontend minus 200 MHz.
Base-frequency:
set the start frequency of the frequency ramps (in MHz). The start frequency f
B
should be at least 100 MHz larger than the minimum supported frequency f
min
of the frontend, and
at least 100 MHz smaller than the maximum supported frequency of the frontend f
max
minus the
desired bandwidth.
If the base-frequency and bandwidth are chosen in a way that the
bandwidth exceeds the minimum and maximum supported frequencies of the frontend, the
voltage applied to the VCO for the voltage ramp may drive into saturation, which decreases
the signal quality.
3.2.5 Baseband Processing Settings (BB Processing Tab)
The ‘BB Processing’ tab shown in Figure 16 is used to control the baseband processing of the
sensor to tune the SNR, accuracy, or processing speed.
Setting
Description
Ramp time
shows the calculated ramp time per ramp
ADC clock divider
adjust the sampling frequency indirectly
Number of samples
adjust the number of samples per ramp
Number of ramps
adjust the number of ramps used for SNR
reduction
Downsampling
adjust the number of samples that are
averaged after sampling
FFT size
adjust the number of FFT bins
Average n
adjust the number of FFTs to average
MTI-Mode
activate / deactivate the Moving Target
Indicator mode
Figure 16: BB Processing tab of the Control Panel