4.5 Frequency Response
The frequency response of the meter can be determined in the GUI to ensure the excitation frequency is optimal.
A "Frequency Sweep" is initiated by first setting the desired starting excitation frequency in the "Configuration"
tab. After this has been set, set the number of "Captures" and "Step Size" to cover the band of interest. In
name and then initiates the sweep.
Figure 4-11. Frequency Sweep Peak Amplitudes
From this sweep, 1020 kHz appears to be a good excitation frequency for this meter. The process for tuning the
configuration to an optimal value can be summarized as follows:
Note
Steps 1 to 3 should have already been completed in
1. Set the "Transmit Frequency" to the nominal frequency of the transducer.
2. Adjust the "Gap between pulse start and ADC capture" and "Capture Duration" parameters to capture the
complete signal in the "ADC Capture" window.
3. Adjust the "Gain" setting to get a signal which has an amplitude of ±900 ADC counts.
4. Set the "Transmit Frequency" to a frequency which is 200 kHz less than the nominal frequency of the
transducer and conduct a frequency sweep which ends at a frequency 200 kHz greater than the nominal
frequency of the transducer.
5. Identify the peak amplitude of the "Frequency Sweep" and set the "Transmit Frequency" to this value.
USS GUI
SLAU810B – SEPTEMBER 2019 – REVISED SEPTEMBER 2020
Water Flow Meter
15
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