A wireless communication created by a computer software activity is described and modelled. The generation of this communication link is a consequence of electromagnetic (EM) emanations emitted during computer activity. This wireless channel in addition to channel errors due to noise, also experiences jitter created by the software activity "transmitter" which lacks precise synchronization. Also, the "transmitter" gets interrupted with other (system) activity, and the transmitted signal goes through a channel obstructed by metal, plastic, etc. To capture all these effects, we have modelled transmitted sequence as a pulse amplitude modulated (PAM) signal with random varying pulse position. From the model, we have derived the power spectral density and the bit error rate of the transmitted signal and presented performance analysis of such a channel.