Patent ID: 7920648

Claim:
Apparatus for preparing a signal, which is one of the UMTS and GSM signal, and has been received at a wireless communications device, to be processed by a receiver which will attempt to recover information conveyed by the signal, the apparatus comprising: a filter to filter the signal in a digital form having samples appearing at a sample rate; and an adjuster to adjust the sample rate, wherein the filter filters the signal in both a first manner which is required when the receiver is a UMTS receiver and a second manner which is required when the receiver is a GSM receiver, wherein the adjuster performs adjustments to the sample rate when the receiver is the GSM receiver and the adjustments comprise altering the sample rate before the signal is filtered to permit the filter to perform filtering in the second manner and altering, using a combination of an interpolator followed by a decimator, the sample rate after the signal has been filtered to provide the signal with a sample rate required by the GSM receiver, whereas the filter performs filtering in the first manner without the adjustments to the sample rate when the receiver is the UMTS receiver, wherein the filter comprises an FIR filter with adjustable tap coefficients which can be adjusted to allow the filter to perform filtering in the first manner and in the second manner.