Half-band Interpolator - 7.2 English

FIR Compiler (PG149)

Document ID
PG149
Release Date
2022-10-26
Version
7.2 English

Just as the half-band decimator is an optimized version of the more general polyphase decimation filter, the half-band interpolator is a special case of a polyphase interpolator. This Figure shows the half-band interpolator.

Figure 3-32: Half-band Interpolation Filter

X-Ref Target - Figure 3-32

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The coefficient set for a true half-band interpolator is identical to that of a half-band decimator with the same specifications. The large number of zero entries in the impulse response is exploited in exactly the same manner as with the half-band decimator to produce hardware-optimized half-band interpolators. The process is presented in This Figure . This Figure (a) is the impulse response, This Figure (b) shows the polyphase partition, and This Figure (c) is the optimized architecture that has taken full advantage of the 0 entries in the coefficient data, along with coefficient symmetry.

The high density of zero-valued filter coefficients is exploited in the FPGA realization to produce a minimal area implementation.

Figure 3-33: 7-Tap Half-band Interpolation Filter

X-Ref Target - Figure 3-33

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7_tap_half_band_int_filt_b_pg149.jpg

7_tap_half_band_int_filt_c_pg149.jpg