Data processing

Spike2 contains advanced features for processing waveform and timestamp data. Waveforms can be modified and information passed between channel types, for example marking times of detected waveform features or converting event data to waveform for analysis of frequency content.

Channel processes

A channel process is an operation applied dynamically to waveform data. Although the original data is not changed in any way, the user sees the processed data. Multiple processes can be applied and removed at any time - see a video demonstration

  • Processes include rectify, smooth, DC remove, slope, time shift, downsample, interpolate, match channel sample rate, median filter and RMS amplitude
  • Apply processes on-line or off-line
  • Duplicate channels for simultaneous display of raw and processed data

EMG data with duplicated channels showing
rectification and smoothing

Digital filtering

Digital FIR (Finite Impulse Response) and IIR (Infinite Impulse Response) filters can be applied to waveform data. Both types are set up using interactive dialogs with the following functions:

  • View filter response and preview effect before applying filter
  • Save and restore filters for later use
  • Drag filter features or edit filter values

FIR filter types include high pass, low pass, band pass and band stop (1, 1½ and 2 bands) and differentiators with control of band edges and steepness of cutoff. FIR filters are unconditionally stable and impose no phase delay, so peaks and troughs do not move when data is filtered.

IIR filter types include notch and resonator filters plus low pass, high pass, band pass and band stop, modelled on Butterworth, Bessel and Chebyshev analogue filters. IIR filters allow steeper edges and narrower notches than FIR filters for the same computational effort.

Digital FIR filtering


Spike2 includes a number of channel processing options that can be applied to waveform or RealWave data channels. Channel processes are dynamic and do not affect the data stored on disk, but use the raw data to display a calculated version of the processed trace on-screen. This video tutorial shows how to apply channel processes to different types of data.

Cambridge Electronic Design Limited

Registered in England: 972132

Registered office:

  • Cambridge Electronic Design Limited,
  • Technical Centre,
  • 139 Cambridge Road,
  • Milton,
  • Cambridge CB24 6AZ

VAT: GB 214 2617 96

Producer Registration number: WEE/BD0050TZ

Terms and Conditions of Sale

For our US customers, we can provide tax form W-8BEN, that identifies us as a UK company.

DUNS: 219151016
NAICS: 423490
Commodity codes
Hardware: 84716070
Software: 85234945

By email:

By post:
  • Cambridge Electronic Design Limited,
  • Technical Centre,
  • 139 Cambridge Road,
  • Milton,
  • Cambridge CB24 6AZ
By telephone:

(Int.+44) (0)1223 420186

From North America (Toll Free):

1 800 345 7794


Privacy policy

CED, through this site, does two things that relate to privacy. We would like to explain them.

Emails from down-loads

We offer free down-loads of many files on our site, from test programs to complete install files for updated versions of major packages like Spike2 and Signal.

When customers wish to take a down-load of a major package, we ask a few questions, including their name, email address, the serial number of the software for which they seek an upgrade and whether they would like an automatic email whenever we update the product. This information is emailed back to CED when they access the final down-load screen. Within this email, your browser transmits the type and version of browser you are using, and the screen resolution you are running.

The reasons why we take and keep this information are that it is useful for our software development team to know who has taken the latest versions, and it is useful for our web site development team to know which browsers people are using to view our site, and what resolution they have their screens set to.


When people down-load a major package, we try to write a cookie, a small file in your computer, that records your name, serial number of the software package, and the version you are down-loading. These files have a lifetime of one year.

The reasons for storing this information are firstly that if you ask for another down-load some other time, your details are read from the cookie and are pre-written into the form, to save you looking them up again. The other reason is that next time you access our site, your browser looks through your CED cookies and compares the versions down-loaded with the latest version numbers read from our site. If there is a later version of a product you have already down-loaded, we tell you on the home page screen, so you know that it is worth going to the down-load page again.

None of this information is ever given to anyone outside CED. ×