Fractional Delay Farrow Filter
The Fractional Delay Farrow Filter is a digital filter that delays the discrete-time input signal by a fraction of the sample period. There are many applications where such a delay is necessary. As an example one can consider symbol synchronization in digital receivers, conversion between arbitrary sampling frequencies, echo cancellation, speech coding and speech synthesis, modeling of musical instruments, etc.
Summary
This article explains the Fractional Delay Farrow Filter and how polynomial Farrow structures implement fractional-sample delays for discrete-time signals. It covers design methods, error and group-delay tradeoffs, and practical implementation considerations for applications such as symbol synchronization, speech/audio processing, and echo cancellation.
Key Takeaways
- Describe the Farrow filter architecture and how polynomial basis functions produce fractional delays.
- Design polynomial coefficient sets using methods like Lagrange interpolation and least-squares optimization.
- Analyze approximation error, phase/group-delay behavior, and bandwidth limitations for chosen polynomial orders.
- Implement Farrow filters in real-time systems, including fixed-point considerations and low-latency deployment.
Who Should Read This
DSP engineers, signal-processing researchers, and graduate students with some prior DSP experience who need to design or implement fractional-sample delays for communications, audio/speech, or radar systems.
TimelessIntermediate
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