一个nalysis Filter Bank (Channelizer)

The generic analysis filter bank, also known as the channelizer, consists of a series of parallel bandpass filters that split an input broadband signal,X[[n这是给予的，，，，into a series of narrow subbands. Each bandpass filter retains a different portion of the input signal. After the bandwidth is reduced by one of the bandpass filters, the signal is downsampled to a lower sample rate commensurate with the new bandwidth.

过滤器库中的第一个分支包含一个低通滤波器，H₀（（z), which acts as a prototype filter. The remaining filtersH₁（（z） 通过H_m-1（（z) are modulated versions of this filter. These modulated versions can be rearranged in terms of a complex exponential (modulation factor) followed by the prototype lowpass filterH₀（（z).

y₁[[m这是给予的，，，，y₂[[m]，…，，y_M-1[[m]是狭窄的子带信号转换为基带。

For more details on this structure, see一个nalysis Filter Bank。

可以使用多相结构有效地实现此过滤库。有关多相结构及其如何实现的更多详细信息dsp.Channelizerobject and theChannelizer块，请参阅Channelizer算法。The chief advantage of this polyphase implementation is that you can downsample the signal prior to filtering, thereby allowing you to filter the signal at a lower sample rate.

Synthesis Filter Bank (Channel synthesizer)

The synthesis filter bank, also known as the channel synthesizer, consists of a set of parallel bandpass filters that merge multiple input narrowband signals,y₀[[m这是给予的，，，，y₁[[m这是给予的，，，，y₂[[m]，…，，y_M-1[[m]进入单个宽带信号，v[[n这是给予的。The input narrowband signals are in the baseband. Each narrowband signal is interpolated to a higher sample rate by using the upsampler, and then filtered by the lowpass filter. A complex exponential that follows the lowpass filter centers the baseband signal aroundw_k， 在哪里 $$w_k=2\pi k/m$$and $$k=0，，，，1，，，，2，，，，\mathrm{...}，，，，m-1$$。

该过滤库是使用所描述的多相结构进行有效实现的Channel Synthesizer Algorithm。Thedsp.ChannelSynthesizerobject and theChannel Synthesizerblock in DSP System Toolbox™ use this implementation.

两通道（半频带）过滤库

Two-channel filter bank is a special case of the genericm-channel filter bank, where the number of filter branches is two.

The DFT matrix of the analysis portion looks like the following matrix.

第一行添加了两个多相分支以给出低通子带输出。第二行减去两个多相分支以给出高通子带输出。如本图所示，DSP系统工具箱中的半频带脱离器对象和块实现了其算法。一个₀（（z) and一个₁（（z) are the allpass polyphase components. This structure is the analysis portion of the two-channel halfband filter bank. Due to the halfband nature of the filters, one of the branches in this polyphase structure becomes a pure delay component.

For more details on this structure and its derivation, seePolyphase Implementation在下面一个lgorithms在这些参考页面上。

同样,halfband插入器对象和blocks in DSP System Toolbox implement their algorithm as shown in this diagram. This structure is the synthesis portion of the two-channel halfband filter bank. Due to the halfband nature of the filters, one of the branches in this polyphase structure becomes a pure delay component.

For more details on this structure and its derivation, seePolyphase Implementation在下面一个lgorithms在这些参考页面上。

The other two-channel filter bank features that DSP System Toolbox offers let you specify the lowpass and highpass filter coefficients. These features can customize the partitioning of the broadband signal. For an example, seeReconstruction Through Two-Channel Filter Banks。

您可以将子带分析和合成过滤器库用作基本单元，并创建多级过滤器库。有关更多详细信息，请参阅多级过滤库。