BioSigRZ filters not working correctly - high frequency noise in ABR data

Tech Note: TN0883
Product: BioSigRZ
Version: 5.0
Date Added: 2010-10-22

Issue

In version 5.0, all acquisition filter settings are erroneously multiplied by 8x, so a 3 kHz low-pass filter is actually at 24 kHz. This will result in more high frequency noise in the recordings. Also, thresholds will be higher than normal because the high-pass filter is higher than it should be and is filtering out some of the ABR signal. ABR acquisition occurs at 200 kHz instead of 25 kHz.

Solution

Upgrade to the latest version of BioSigRZ and TDT Drivers. This issue was resolved in BioSigRZ version 5.1.