CN211959174U - FIR low pass filter - Google Patents

Abstract

An FIR low-pass filter is arranged between a data source and a host computer, and the filter includes a lower filter actuator and an upper parameter control mechanism; the lower filter actuator includes an input interface, a storage module, a storage module, a A data operation module and an output interface, wherein the input interface is communicatively connected with the data source, and the output interface is communicatively connected with the host computer; the host parameter control mechanism includes a filter parameter interface, a filter coefficient calculation module, a filter The filter coefficient quantization module and the upper communication interface, the filter parameter interface is communicatively connected with the upper computer, the filter coefficient quantization module is also communicatively connected with the filter parameter interface, and the upper communication interface is communicatively connected with the input interface. The invention provides an FIR low-pass filter, which can change the filter coefficients in real time according to requirements, realize the required filtering function, and has stronger flexibility.

Description

A FIR low-pass filter

technical field

The utility model relates to the field of filters, in particular to an FIR low-pass filter.

Background technique

FIR (Finite Impulse Response) filter is a finite-length unit impulse response filter, also known as a non-recursive filter, which is the most basic component in a digital signal processing system. The linear phase-frequency characteristic of , and its unit sampling response is finite, so the filter is a stable system. Therefore, FIR filters are widely used in communication, image processing, pattern recognition and other fields.

At present, the hardware implementation of FIR filters is mainly realized by integrated circuits, digital signal processing chips or programmable logic devices. Different implementations have different advantages and different application scenarios. For example, integrated circuits have simple structure and low cost, but their performance is limited. , suitable for steady-state systems that do not require high filtering performance. However, either way, there is a shortcoming, that is, the flexibility is poor, and it is difficult to adjust the filtering parameters according to the current filtering requirements in practical applications.

SUMMARY OF THE INVENTION

In order to solve the deficiencies in the prior art, the utility model provides an FIR low-pass filter, which can change the filter coefficients in real time according to the requirements, realize the required filtering function, and has stronger flexibility.

In order to achieve the above purpose, the specific scheme adopted by the present utility model is: an FIR low-pass filter, which is arranged between the data source and the upper computer, and the filter includes a lower filtering actuator and an upper parameter control mechanism; the lower The filtering execution mechanism includes an input interface, a storage module, a data operation module and an output interface that are connected in sequence in communication, wherein the input interface is communicatively connected with the data source, and the output interface is communicatively connected with the upper computer; the upper parameter control mechanism includes sequentially A filter parameter interface, a filter coefficient calculation module, a filter coefficient quantization module and a host communication interface connected in communication, the filter parameter interface is communicated with the host computer, the filter coefficient quantization module is also communicated with the filter parameter interface, and the host communication interface connected in communication with the input interface.

As a further optimization of the above-mentioned FIR low-pass filter: the input interface includes a data input interface and a lower communication interface, the storage module includes an input data buffer submodule and a filter coefficient storage submodule, and the data input interface and the input data buffer submodule The modules are connected in communication, the lower communication interface is in communication connection with the filter coefficient storage submodule and the upper communication interface, and the input data buffer submodule and the filter coefficient storage submodule are in communication connection with the data operation module.

As a further optimization of the above FIR low-pass filter: the storage module further includes an output data cache sub-module, and the output data cache sub-module is connected in communication with both the data operation module and the output interface.

As a further optimization of the above FIR low-pass filter: the upper communication interface and the lower communication interface are communicatively connected through the FSMC bus.

As a further optimization of the above-mentioned FIR low-pass filter: the data operation module is set as a fast convolution module.

As a further optimization of the above-mentioned FIR low-pass filter: the filtering parameter interface is set as an SPI interface.

As a further optimization of the above FIR low-pass filter: both the input interface and the output interface are set as parallel interfaces.

Beneficial effects: The utility model can realize the set filtering function through calculation according to the filtering requirements, and can adjust in real time, and has strong flexibility.

Description of drawings

Figure 1 is a block diagram of the overall structure of the present invention.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Please refer to Figure 1, an FIR low-pass filter, which is set between the data source and the upper computer, and the filter includes a lower filtering actuator and an upper parameter control mechanism.

The lower filter actuator includes an input interface, a storage module, a data operation module and an output interface which are connected in sequence in communication, wherein the input interface is connected in communication with the data source, and the output interface is connected in communication with the upper computer. The input interface is used to obtain the pre-filtering data from the data source; the storage module is used to cache the pre-filtering data, the control parameters from the upper parameter control mechanism, and the filtered data obtained after the data operation module calculates the pre-filtering parameters; data operation The module is used to calculate the pre-filtered data to obtain the filtered data, that is, to perform the filtering process; the output interface is used to upload the filtered data to the host computer.

The upper parameter control mechanism includes a filter parameter interface, a filter coefficient calculation module, a filter coefficient quantization module and an upper communication interface connected in communication, the filter parameter interface is communicated with the upper computer, and the filter coefficient quantization module is also communicated with the filter parameter interface. The upper communication interface is connected to the input interface for communication. The filter parameter interface is used to receive filter parameters such as window function, order, sampling frequency and cut-off frequency from the upper computer, as well as output the calculated filter coefficient and the quantized value of the filter coefficient from the upper computer; filter coefficient calculation The module is used to calculate the filter coefficients according to the parameters received by the filter parameter interface; the filter coefficient quantization module is used to quantize the filter coefficients calculated by the filter coefficient calculation module, so that it can be applied to the lower filter actuator Medium; the upper communication interface is used to transmit the quantized filter coefficients to the lower communication interface.

When in use, first send the filter parameters to the upper parameter control mechanism through the upper computer; then the filter coefficient calculation module calculates the filter coefficients according to the filter parameters and sends the filter coefficients to the upper computer through the filter parameter interface; then filter The filter coefficient quantization module quantizes the filter coefficients, obtains the quantized coefficients, and sends the quantized coefficients to the data operation module through the upper communication interface and the input interface, and sends the quantized coefficients to the upper computer through the filter parameter interface; The data source obtains the data before filtering and sends it to the data operation module; then the data operation module calculates the data before filtering according to the quantization coefficient to obtain the filtered data, and sends the filtered data to the host computer through the output interface to complete the filtering process.

The utility model can realize the set filtering function through calculation according to the filtering requirements, and can be adjusted in real time, and has strong flexibility.

Considering the different forms of the data before filtering and the quantization coefficients, in order to avoid converting the data before filtering and the quantization coefficients respectively, the input interface includes a data input interface and a lower communication interface, and the storage module includes an input data cache sub-module and a filter coefficient storage sub-module. module, the data input interface is communicatively connected to the input data buffer sub-module, the lower communication interface is communicatively connected to the filter coefficient storage sub-module and the upper communication interface, and the input data buffer sub-module and the filter coefficient storage sub-module communicate with the data operation module. connect. The data input interface is connected to the data source for communication, and is used to obtain the data before filtering from the data source. The lower communication interface is used to obtain the quantized filter coefficients from the upper communication interface. The data and filter coefficients can be adjusted according to the data source and the type of the upper communication interface, thereby avoiding data conversion, which can improve the operating efficiency of the filter and the accuracy of the filtering result.

On the basis that the data before filtering and the quantization parameters are stored separately, the storage module also includes an output data cache sub-module. The output data cache sub-module is connected in communication with the data operation module and the output interface. The three types of data involved in the filter are respectively Storage can improve data management efficiency and ensure data security.

In a specific embodiment of the present utility model, the lower filter actuator adopts FPGA, the model is EP4CE10F17C8N, the upper parameter control mechanism adopts STM32F407IFT6 single-chip microcomputer; the data operation module is set as a fast convolution module; the input data buffer sub-module and filter coefficient storage The sub-module is implemented by the built-in RAM of the FPGA, with a bit width of 16 bits and a depth of 2048; the output data cache sub-module is implemented by the built-in RAM of the FPGA, with a bit width of 32 bits and a depth of 2048; the filter parameter interface is set to serial Peripheral interface; both the input interface and output interface are set to parallel interface, the data bus width of the input interface is 16 bits, the data bus width of the output interface is 16 bits, the data is sent on both edges, the rising edge sends 16-bit data, and the falling edge sends the high 16-bit data. Bit data; the upper communication interface and the lower communication interface are connected through the FSMC bus communication; the filter coefficient calculation module and the filter coefficient quantization module are implemented by the calculation core of the ARM single-chip microcomputer.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. a kind of FIR low-pass filter, is arranged between data source and host computer, it is characterized in that: described filter comprises lower filter executive mechanism and upper parameter control mechanism; The lower filter implementing mechanism comprises an input interface, a storage module, a data operation module and an output interface that are connected in communication in sequence, wherein the input interface is communicatively connected to the data source, and the output interface is communicatively connected to the upper computer; The upper parameter control mechanism includes a filter parameter interface, a filter coefficient calculation module, a filter coefficient quantization module and an upper communication interface that are sequentially connected in communication, the filter parameter interface is communicated with the upper computer, and the filter coefficient quantization module is also connected to the filter The parameter interface is in communication connection, and the upper communication interface is in communication connection with the input interface. 2. a kind of FIR low-pass filter as claimed in claim 1 is characterized in that: described input interface comprises data input interface and lower communication interface, and described storage module comprises input data buffer module and filter coefficient storage module module, the data input interface is communicatively connected with the input data buffer submodule, the lower communication interface is connected in communication with the filter coefficient storage submodule and the upper communication interface, and the input data buffer module and the filter coefficient storage submodule are all connected with the described upper communication interface. Data operation module communication connection. 3. a kind of FIR low-pass filter as claimed in claim 2 is characterized in that: described storage module also comprises output data buffer submodule, output data buffer module and described data operation module and described output interface are all communication connection. 4 . The FIR low-pass filter according to claim 2 , wherein the upper communication interface and the lower communication interface are communicatively connected through an FSMC bus. 5 . 5. The FIR low-pass filter according to claim 1, wherein the data operation module is set as a fast convolution module. 6 . The FIR low-pass filter according to claim 1 , wherein the filtering parameter interface is set as an SPI interface. 7 . 7 . The FIR low-pass filter according to claim 1 , wherein the input interface and the output interface are both set as parallel interfaces. 8 .

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