The process of digitally converting the sampling rate a tip- nal from a given rate F = 1/T to a different rate F’ = 1/T is called sampling rate conversion. In this paper, a multirate sampling filter is designed by using multiple constant multiplication (MCM). IF Subsampling with Complex Multirate Filters. This is achieved by replacing the multipliers in generalized rational sampling rate converter (GRSRC) with codes derived from MCM algorithm. Although at times it appears counter intuitive, the technique is an exceptionally useful one. However in the case of fractional sample rate conversion, the number of phases, and therefore the filter order, can quickly become excessively high. Abstract. DSP: Efficient Sample Rate Conversion Rational Sample Rate Conversion Example: Suppose we wish to change the sampling rate by a factor of 50 49. Upsample by factor of L=50. 2. The 8 kHz data is pulled from memory and converted to a 64 kHz sampling rate, a procedure called interpolation. ... (DDC). Downsample by factor of M =49. sampling rates in which case it may be necessary to convert sampling rates of signals in system from one rate to another. Chapter 11: Multirate Digital Signal Processing11.1 Introduction Sampling Rate Conversion 0 n original/bandlimited interpolated signal x(n) x(t) 1 y(n) Ix(n): original samples at sampling rate F x Iy(n): new samples at sampling rate F y A concise description of sampling rate conversion and multi-rate sampling has been presented.

Multirate techniques can also be used in the output portion of our example system. specified sampling rate can be converted into another signal with a target sampling rate without destroying the signal components of interest. Multirate simply means “multiple sampling rates”. Furthermore, the frequency translation-based bandpass filter model is a core element of the modulation-based uniform filterbanks to be discussed in the sequel. The multirate filter implementation means that down-sampling or up-sampling operations are embedded into the filter structure. In multirate applications, the computational requirements for FIR filters can be reduced by the sampling rate conversion factor as demonstrated in Chapter IV. Lowpass filter with cutoff frequency π 50. The DDC is a key component of digital radios. 3.

as illustrated in Fig. To resample a signal from 8 kHz to 44.1 kHz, we interpolate by 441 and decimate by 80 (8*441/80=44.1). Convolution followed by downsampling is the basic step in the computation of the discrete wavelet transform (DWT). Chapter 11: Multirate Digital Signal Processing11.5 Implementation of Sampling Rate Conversion Polyphase Structures of Decimation Filters IUse of theNoble identityallows reduction of number of multiplications and additions, since ltering is performed at a

In multirate applications, the computational requirements for FIR filters can be reduced by the sampling rate conversion factor as demonstrated in Chapter IV. The demand of multirate signal processing applications to support sample rate conversion techniques are increased without any degradation. However, such a degree of computation savings cannot be achieved in multirate implementations of IIR filters. Polyphase structures are generally considered efficient implementations of multirate filters. 10.1(a). D. Richard Brown III 2 / 6 Furthermore, the frequency translation-based bandpass filter model is a core element of the modulation-based uniform filterbanks to be discussed in the sequel. Multirate techniques are used in filters for sampling rate conversion where the input and output rates are different, and also in constructing filters with equal input and output rates. Sampling and Multirate Techniques for Complex and Bandpass Signals Markku Renfors ... completely by discrete-time samples if the sampling rate (1/T) is at least 2W. The input signal x(n) is characterized by the sampling rate FI = 1/Tx and the output signal y(m) is characterized by the sampling rate Fy = where and are the corre- sponding sampling intervals. Therefore in order to enhance the performance of multirate filter in terms of area, speed and computational complexity, various filter structures with different methods were designed. A multirate DSP system uses multiple sampling rates within the system.