The CED 4001-16 Mains Pulser generates mains-frequency-locked pulses that can be used to reduce the magnitude of mains pickup (‘hum’) in recorded signals. The output is on a BNC connector, double-isolated from mains and consists of a train of 150 microsecond positive-going 5V TTL pulses, suitable for direct connection to a 1401 Event input.
The Mains Pulser will run off any mains supply between 100 -240 V AC, 50 - 60 Hz. The case is earthed to mains earth. Current consumption is less than 100 mA.
Box size: 104mm x 126mm x 53mm (W x D x H).
The recommended method of use is to record the pulses on an Event channel, alongside the waveform signal. Hum removal can then be done off-line, for example by using the Spike2 scripts HumRemove or HumRemoveExpress. Averaging with respect to the mains-generated pulses gives a good copy of the hum component, which can be subtracted from the polluted signal to provide a cleaner version. Click on the video tutorial on the right for a demonstration.
Mains ‘hum’ is often complex and composed of odd harmonics of the mains frequency, making it very difficult to remove or suppress using simple high pass or notch filters. HumRemoveExpress.s2s is a Spike2 version 7 script that you can use offline to strip out much of this residual mains interference, making your data much more presentable and easier to analyse. This video tutorial shows how to use the script to remove mains hum.
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