Fir Serial

Find 14 ways to say SERIAL, along with antonyms, related words, and example sentences at, the world's most trusted free thesaurus. The serial number or license key is a code or number generated by the Easysoft License server. So, the key is a combination of machine numbers with some information that can be used to register a program, software, or application. The IDM serial number is the key to registering your Internet Download Manager software and making it a paid version.

Applies a Finite Impulse Response (FIR) filter on a series. The function takes an expression containing a dynamic numerical array as input and applies a Finite Impulse Response filter. By specifying the filter coefficients, it can be used for calculating a moving average, smoothing, change.

Hello there, fellow Arduino Programmers. Tv serial killers.

Fir full episodes

I spent my day (well, part of it at least) programming a FIR (or Finite Impuls Response) filter on the Arduino.


It can be used as a building block for any program that requires some form of filtering. Because of its simple nature, you may use this for various purposes:

  • filtering audio (duh…)
  • smoothing of analog inputs
  • smoothing of PWM outputs (ramp up, and down of motors, gradually turning lights/LED’s on and off)
  • taking a ‘running average’ on streaming data
  • removing ‘DC’ or static components of a signal (requires a ‘high pass’ or ‘band pass’ filter

I’ve written this to sharpen my limited C-programming skills, so there is probably lots of room for improvement. I hope people will criticize my code, so I can learn to write proper code, and optimize it. Once optimized, I hope this code could make it into the ‘playground’. I guess if it handled INT’s it would be more useful there.

I’ve commented the code extensively, so people could understand what it going on, and change it to their own needs.

Please, feel free to comment and post alternatives!

Rene Knuvers
Goirle, The Netherlands
[email protected]

This example illustrates how to generate HDL code for a symmetrical FIR filter with fully parallel, fully serial, partly serial and cascade-serial architectures for a lowpass filter for an audio filtering application.


Design the Filter

Use an audio sampling rate of 44.1 kHz and a passband edge frequency of 8.0 kHz. Set the allowable peak-to-peak passband ripple to 1 dB and the stopband attenuation to -90 dB. Then, design the filter using fdesign.lowpass, and create the FIR filter System object using the 'equiripple' method with the 'Direct form symmetric' structure.

Quantize the Filter

Fir Serial Episode 1132 Youtube


Assume that the input for the audio filter comes from a 12 bit ADC and output is a 12 bit DAC.

Generate Fully Parallel HDL Code from the Quantized Filter

Starting with the correctly quantized filter, generate VHDL or Verilog code. Create a temporary work directory. After generating the HDL code (selecting VHDL in this case), open the generated VHDL file in the editor by clicking on hyperlink displayed in the command line display messages.

This is the default case and generates a fully parallel architecture. There is a dedicated multiplier for each filter tap in direct form FIR filter structure and one for every two symmetric taps in symmetric FIR structure. This results in a lot of chip area (78 multipliers, in this example). You can implement the filter in a variety of serial architectures to obtain the desired speed/area trade-off. These are illustrated in further sections of this example.

Generate a Test Bench from the Quantized Filter

Generate a VHDL test bench to make sure that the result matches the response you see in MATLAB® exactly. The generated VHDL code and VHDL testbench can be compiled and simulated using a simulator.

Generate DTMF tones to be used as test stimulus for the filter. A DTMF signal consists of the sum of two sinusoids - or tones - with frequencies taken from two mutually exclusive groups. Each pair of tones contains one frequency of the low group (697 Hz, 770 Hz, 852 Hz, 941 Hz) and one frequency of the high group (1209 Hz, 1336 Hz, 1477Hz) and represents a unique symbol. You will generate all the DTMF signals but use one of them (digit 1 here) for test stimulus. This will keep the length of test stimulus to reasonable limit.

Next, let's generate the DTMF tones

Information Regarding Serial Architectures

Serial architectures present a variety of ways to share the hardware resources at the expense of increasing the clock rate with respect to the sample rate. In FIR filters, we will share the multipliers between the inputs of each serial partition. This will have an effect of increasing the clock rate by a factor known as folding factor.

You can use hdlfilterserialinfo function to get information regarding various filter lengths based on the value of coefficients. This function also displays an exhaustive table of possible options to specify SerialPartition property with corresponding values of folding factor and number of multipliers.

You can use the optional properties 'Multipliers' and 'FoldingFactor' to display the specific information.

Fully Serial Architecture

F I R Sab Tv

In fully serial architecture, instead of having a dedicated multiplier for each tap, the input sample for each tap is selected serially and is multiplied with the corresponding coefficient. For symmetric (and antisymmetrical) structures the input samples corresponding to each set of symmetric taps are preadded (for symmetric) or pre-subtracted (for anti-symmetric) before multiplication with the corresponding coefficients. The product is accumulated sequentially using a register and the final result is stored in a register before the next set of input samples arrive. This implementation needs a clock rate that is as many times faster than input sample rate as the number of products to be computed. This results in reducing the required chip area as the implementation involves just one multiplier with a few additional logic elements like multiplexers and registers. The clock rate will be 78 times the input sample rate (foldingfactor of 78) equal to 3.4398 MHz for this example.

To implement fully serial architecture, use hdlfilterserialinfo function and set its 'Multipliers' property to 1. You can also set the 'SerialPartition' property with its value equal to the effective filter length, which in this case is 78. The function also returns the folding factor and number of multipliers used for that serial partition setting.

Generate the testbench the same way, as in the fully parallel case. It is important to generate a testbench again for each architecture implementation.

Partly Serial Architecture

Fully parallel and fully serial represent two extremes of implementations. While Fully serial is very low area, it inherently needs a faster clock rate to operate. Fully parallel takes a lot of chip area but has very good performance. Partly serial architecture covers all the cases that lie between these two extremes.

The input taps are divided into sets. Each set is processed in parallel by a serial partition consisting of multiply accumulate and a multiplexer. Here, a set of serial partitions process a given set of taps. These serial partitions operate in parallel with respect to each other but process each tap sequentially to accumulate the result corresponding to the taps served. Finally, the result of each serial partition is added together using adders.

Partly Serial Architecture for Resource Constraint

Let us assume that you want to implement this filter on an FPGA which has only 4 multipliers available for the filter. You can implement the filter using 4 serial partitions, each using one multiply accumulate circuit.

The input taps that are processed by these serial partitions will be [20 20 20 18]. You will specify SerialPartition with this vector indicating the decomposition of taps for serial partitions. The clock rate is determined by the largest element of this vector. In this case the clock rate will be 20 times the input sample rate, 0.882 MHz.

Partly Serial Architecture for Speed Constraint

Assume that you have a constraint on the clock rate for filter implementation and the maximum clock frequency is 2 MHz. This means that the clock rate can't be more than 45 times the input sample rate. For such a design constraint, the 'SerialPartition' should be specified with [45 33]. Note that this results in an additional serial partition hardware, implying additional circuitry to multiply-accumulate 33 taps. You can specify SerialPartition using hdlfilterserialinfo and its property 'Foldingfactor' as follows.

In general, you can specify any arbitrary decomposition of taps for serial partitions depending on other constraints. The only requirement is that the sum of elements of the vector should be equal the effective filter length.

Cascade-Serial Architecture

The accumulators in serial partitions can be re-used to add the result of the next serial partition. This is possible if the number of taps being processed by one serial partition must be more than that by serial partition next to it by at least 1. The advantage of this technique is that the set of adders required to add the result of all serial partitions are removed. However, this increases the clock rate by 1, as an additional clock cycle is required to complete the additional accumulation step.

Cascade-Serial architecture can be specified using the property 'ReuseAccum'. This can be done in two ways.

Add 'ReuseAccum' to generatehdl method and specify it as 'on'. Note that the value specified for 'SerialPartition' property has to be such that the accumulator reuse is feasible. The elements of the vector must be in descending order except for the last two which can be same.

If the property 'SerialPartition' is not specified and 'ReuseAccum' is specified as 'on', the decomposition of taps for serial partitions is determined internally. This is done to minimize the clock rate and to reuse the accumulator. For this audio filter, it is [12 11 10 9 8 7 6 5 4 3 3]. Note that it uses 11 serial partitions, implying 11 multiply accumulate circuits. The clock rate will be 13 times the input sample rate, 573.3 kHz.

Fir Serial Characters Real Name

Optimal decomposition into as many serial partitions required for minimum clock rate possible for reusing accumulator.


You designed a lowpass direct form symmetric FIR filter to meet the given specification. You then quantized and checked your design. You generated VHDL code for fully parallel, fully serial, partly serial and cascade-serial architectures. You generated a VHDL test bench using a DTMF tone for one of the architectures.

You can use an HDL Simulator to verify the generated HDL code for different serial architectures. You can use a synthesis tool to compare the area and speed of these architectures. You can also experiment with and generating Verilog code and test benches.