Noisy ABR recordings using an RX6 and BioSigRP

Tech Note: TN0202
Product: RX6
Version: All
Date Added: 2005-11-22


When ABRs that are recorded using the RX6 to present the stimulus appear noisy, the problem might be due to the stimulus sample rate.


The RX6 allows users to select from a wider range of sample rates than other TDT processors. However, when using BioSigRP to record on the Medusa preamplifier, it is necessary to set the stimulus sample rate to an even multiple of the 25 kHz sample rate used on the preamplifier. If the stimulus sample rate is not an even multiple of the recording sample rate, then jitter in the triggering between the two modules will cause the averaged recordings to appear noisy. If a stimulus sample rate is required that is not an even multiple of the 25 kHz on the recording unit, then an external trigger must be used to trigger the stimulus and recording devices.