Patent ID: 7680869
Filing Date: 2010-03-16
Classification: H03H

Abstract:
1. An interpolation filter for interpolating a digital signal, comprising: multiple template filters, which have respective inputs and outputs and an identical template transfer function A(z), which are connected in a cascade such that an input of a given template filter is connected to an output of another template filter that precedes the given template filter in the cascade, and which are arranged to receive and filter an input sequence representing the digital signal sampled at an input sampling rate; ancillary circuitry, which is coupled to receive and process a first subset of the inputs and the outputs of the template filters to produce a first phase output, and to receive and process a second subset of the inputs and the outputs of the template filters, different from the first subset, to produce a second phase output; and a multiplexer, which is arranged to multiplex the phase outputs in order to generate an output sequence having an output sampling rate equal to twice the input sampling rate, wherein the ancillary circuitry is coupled to delay, scale and combine the inputs and outputs in the respective first and second subsets in order to produce the first and second phase outputs.