# Design of Novel FIR Filter Using Add and Shift Multiplier and Carry Save Adder

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**Abstract**

This project investigates the implementation of a
low power FIR filter using Add and Shift Multiplier and Carry
Save Adder. This method is used to reduce the dynamic power
consumption, Delay and Area of a low power FIR filter. This
method include Modified Booth Encoding Algorithm
combined with Spurious Power Suppression Technique, Low
Power Digital Serial Multiplier along with carry look ahead
adder, shift and add multiplier. This proposed FIR filter was
synthesized and implemented using Xilinx ISE V7.1 and also
the power is analyzed using Xilinx XPoweranalyzer.

**I.Introduction **

The impulse response of the filter can be either finite
or infinite. The methods for designing and implementing of
these two filter classes differ considerably. Finite impulse
response (FIR) filters are digital filters whose response to a
unit impulse (unit sample function) is finite in duration. This
is in contrast to infinite impulse response (IIR) filters whose
response to a unit impulse (unit sample function) is infinite in
duration. FIR and IIR filters each have advantages and
disadvantages. FIR filters can be implemented using either
recursive or non-recursive techniques, but usually nonrecursive
techniques are used. FIR filters are widely used in
various DSP applications. In some applications, the FIR filter
circuit must be able to operate at high sample rates, while in
other applications the FIR filter circuit must be a low-power
circuit operating at moderate sample rates.

The low-power or low-area techniques developed
specifically for digital filters. Parallel (or block) processing
can be applied to digital FIR filters to either increase the
effective throughput or reduce the power consumption of the
original filter. Traditionally, the application of parallel
processing to an FIR filter involves the replication of the
hardware units that exist in the original filter. The topology of
the multiplier circuit also affects the resultant power
consumption. They extensively use a modified common sub
expression elimination algorithm to reduce the number of
adders. They have proposed a novel approach for a design
method of a low power digital baseband processing. Their
approach is to optimize the bit-width of each filter coefficient.
They define the problem to find optimized bit-width of each
filter coefficient. This project presents the method to reduce
dynamic switching power of a fir filter using data transition
power diminution technique (DPDT). This technique is used
on adders, booth multipliers. In this research proposes a
pipelined variable precision gating scheme to improve the
power awareness of the system.

**METHODOLOGY:**

A digital filter gives a digital output and consists of digital
components. In a digital filtering application, software running
on a DSP applications and reads the input samples from an
A/D converter. It performs the mathematical manipulations
dictated by the required filter type and output the result as D/A
converter. An analog filter operates directly on the analog
inputs and is built entirely with analog components such as
resistors, capacitors, and inductors. There are many types of
filter used in DSP applications, but the most commonly used
filters are lowpass, highpass, bandpass, and bandstop. A low
pass filter allows only low frequency signals (below some
specified cutoff) through its output and it can be used to
eliminate high frequencies. A low pass filter is small and for
limiting the upper most range of frequencies in an audio
signal.
A high pass filter does the opposite of low pass filter by
rejecting the frequency components below some threshold. An
example high pass application is cutting out the audible 60Hz
AC power "hum", which can be picked up as noise
accompanying almost any signal in the U.S. The designer of a
cell phone or any other sort of wireless transmitter would
typically place an analog bandpass filter in its output RF stage
to ensure only output signals. Engineers mostly use bandstop
filters, because this filter passes both low and high frequencies
to block a predefined range of frequencies in the middle. The
Frequency response Simple filters are usually defined by their
responses to the individual frequency components that
constitute the input signal..

## References:

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