Signal strength

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Signal strength#

HWAAS#

To increase the signal-to-noise ratio (SNR), sampling of points may be repeated and averaged a number of times directly by the sensor itself. The number of samples used for averaging is called hardware accelerated average samples, or HWAAS for short. Using this parameter correctly is crucial for reaching the desired signal quality while limiting the memory usage. For static objects, the SNR grows linearly with HWAAS, but keep in mind that so does the measurement time.

HWAAS scaling#

For A212, HWAAS is controlled per subsweep by three parameters:

  • hwaas_max (default 50, range 1 to 2047): HWAAS at the farthest distance point.

  • hwaas_min (default 1, range 1 to 2047): floor value when distance scaling is active.

  • hwaas_exponent (default 0, range 0 to 4): scaling power applied to the distance ratio.

The effective HWAAS at distance point \(n\) is

\[\text{HWAAS}(n) = \max\!\left(\text{hwaas\_min},\; \text{hwaas\_max} \times \left(\frac{d_n}{d_\text{end}}\right)^{e}\right)\]

where \(d_n\) is the distance at point \(n\), \(d_\text{end}\) is the distance at the last point in the subsweep, and \(e\) is hwaas_exponent. Higher values of \(e\) allocate more averages to far points to compensate for signal energy loss with distance. The goal of this dynamic averaging is to maintain a constant SNR through the measurement range while minimizing power consumption. Commonly used values are 0 (constant HWAAS throughout the sweep), 2 (appropriate for large planar targets such as flat surfaces), and 4 (appropriate for targets with a general three-dimensional shape).

See also

SubsweepConfig for the full list of per-subsweep parameters including hwaas_max, hwaas_min, and hwaas_exponent.

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