Amprobe ULD-410 Manuel De L'utilisateur page 13

4. MAIN APPLICATIONS
*ULD-400-R Filter Operation
In some situations, there might be strong ultrasonic noise generated by running machinery, motion
sensors or other equipment. This noise will cause the Receiver to read the maximum signal strength
on the display regardless of the sensitivity settings and make it unusable for detecting leaks.
In such cases, press the "Filter" button. The firmware will automatically detect the main noise
frequency and filter it out by applying digital non-pass bandwidth filter within +/- 5 kHz. If the
signal level does not decrease down close to 0, then the firmware will automatically repeat the
process for other noise frequencies. Up to three frequencies can be filtered out automatically. The
filter icon will be displayed on the screen and will indicate the number of filters applied, from zero
(no noise detected) to a maximum of three.
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Figure 4.1b: Filter applied
Note: The filter will be applied to the visual signal indication on a screen (signal strength number
and bargraph). The filter will NOT be applied to the audio frequency in order to preserve
original sound of the leak and allow the user to better determine the source of the leak.
Note: When working with the Transmitter, make sure to apply the filter on the Receiver before
the Transmitter is turned on, or in an area where the Transmitter signal can not be detected.
Otherwise, the Transmitter signal frequency will be filtered out and Receiver will not be able
to pick it up.
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