Ratio-variable digital resampling filter

Abstract

The invention discloses a ratio-variable digital resampling filter, which includes a resampling controller and an FD filter. The resampling controller calculates the resampling ratio, monitors the sampling time of the output signal, and calculates the corresponding fractional delay factor. Set the FD filter, monitor the sampling time of the input signal at the same time, and send a filter enable signal to the FD filter at the required moment; after the FD filter receives the filter enable signal, it will delay according to its current fractional delay factor The input signal is filtered, and the filtering result is used as the sampling point corresponding to the sampling time of the output signal. By designing a resampling controller, the invention can realize arbitrary sampling frequency conversion of input data without redesigning filter coefficients.

Description

technical field [0001] The invention belongs to the technical field of digital filters, and more specifically relates to a ratio-variable digital resampling filter. Background technique [0002] In a digital communication system, the symbol rate must be an integer multiple of the sampling rate to ensure that the best sampling point is collected when the symbol timing is restored. Otherwise, there is a deviation in the symbol restoration time, which will seriously affect the demodulation performance. However, in order to meet the needs of various occasions, the symbol rate of the actual signal source and analyzer is wide and continuously variable, while the system sampling rate is fixed, and the relationship between the two often cannot satisfy the integer multiple. Therefore, it is necessary to resample the baseband signal, and complete the conversion from the original rate to the expected rate based on the required resampling ratio. [0003] Resamplers are broadly classifi...

AI Technical Summary

Problems solved by technology

However, the serious problem in the traditional method is that the low-pass filter always works at a high sampling rate, and some of the samples are discarded in the extraction unit, resulting in low system calculation efficiency and large resource consumption; at the same time , when the resampling ratio is large, such as r=98 / 100, there are many points to be interpolated (extracted), the running speed is slow, the efficiency is low, and the storage space is too large

[0008] In the existing variable rate resampling technology, whether it is to design filters online or store a large number of pre-designed filter coefficient tables, it will take up a lot of system resources and storage space. At the same time, the filter design accuracy is limited, and it is difficult to adapt to the accuracy. Increasing application requirements

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