Parks 915-BL, Operating & Service Manual

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915-BL Dual Frequency Doppler
Appendix
Acoustical Output Power
For
US Doppler Products
Parks’ products do not have adjustable output power. Our products are offered over the
frequency ranges of 3.9 - 5.3 MHz (low frequency), and 8.0 MHz - 9.9 MHz (high
frequency). The power output increases with frequency due to the design of the
ultrasound transmitter. Parks uses the same transmitter circuit design for all Doppler
products; therefore, this report applies to all of them.
To insure that the acoustical output power evaluation would show the absolute worse
case acoustical output parameters, Parks had the test done using a model 811-B tuned to
9.8 MHz. The output power was 75 mW, which translated to a maximum P of 20.8 mW
for the probe tuned to the unit. This exhibits an optimal coupling efficiency of 27% for
the crystal transducer.
ONDA report T-4PME02 shows that the maximum global output power was 675.3 mW.
The maximum allowed by the FDA is 720 mW. Parks Medical Electronics, Inc. is
exempt from acoustical output labeling for the US market. Parks has decided to provide
the output power for each probe type even though it is not required.
Acoustic Output Table Track 1, auto scanning mode:
Parks Medical Electronics, Inc. offers several different choices of probes:
Pencil
Skinny Pencil
Adult Flat
Infant Flat
Parks provides the maximum values for each probe model.
Uncertainties for Acoustic Output Table Track 1, auto scanning mode:
Intensity Values ±19.30%
Pressure Values ± 9.65%
Mechanical Index ± 9.65%
Power ±19.30%
Frequency ± 2.00%
The uncertainties listed above and in the following tables are from a test report done by
Onda Labs for Parks’ Medical Electronics, Inc. The test report number is T-5PME01.