The “standard” transmitter definition has restrictions on the highest and lowest valid output pulse frequency for each transmitter. The standard cutoff for the TA and CTA will consider the data invalid below a certain frequency, which is somewhere in the range of 10-15 degrees C.
The LF (Low Frequency) definition removes or lowers this restriction on the lowest valid output frequency in order to continue reporting data past the typically range.
If using the TA-F40 or CTA-F40 for hibernation studies, choose the LF option when selecting the transmitter model.
Once the LF model is selected, new calibration values should be obtained over a range that contains the expected temperatures over which the implant will operate.
Please keep in mind that transmission distance will likely be smaller at the lower temperatures. Also, since low temperatures lower the signal frequency, the signal may be more susceptible to external noise.
- If using the TA-F20 at these temperatures, define it to the TA-F40-LF implant model.
- For the TA-F10, DSI tested 2 devices down to 10 degrees C, using calibration values at 23 and 39 degrees C with the following results:
- At 10 degrees C: ~0.2 degrees C error.
- At 15 degrees C: ~ 0.06 degrees C error.
If the customer recalibrates over a tighter range, the accuracy may be slightly better, no testing has been completed with recalibration.
The operating range of the F40-EET is 34-41 degree C. Below 34 degree C, both the sampling rate and amplitude will decrease. You could recalibrate the temp channel to improve the accuracy by using water bath instructions. Below 18 degree C there will be no biopotential signal at all. There will be a temperature reading, but it will not be accurate. F40-EETs are not recommended for hibernation studies.