The document summarizes the proposed design of a power efficient channelizer for software defined radio using VLSI. It discusses the basic architecture of the channelizer which uses a cascaded integrator-comb (CIC) filter block followed by an 8-point fast Fourier transform (FFT). The CIC filter block contains 5 stages of integrators and 5 stages of comb filters with 1 decimator, totaling 8 complete stages. Simulation results and synthesis results showing the internal blocks and 8-point FFT are also presented. The designed channelizer is concluded to have promising decreases in noise and be suitable for real-time software defined radio channels.
2. Overview
Objective Proposed design of our
Basic architecture of channelizer
channelizer Architecture of our design
CIC filter Simulation results
Fast Fourier transform Synthesis results
What is software defined radio Conclusion
Field programmable gate array Reference
3. objective
The objective of our project is to design a power efficient
channelizer for software defined radio.
We have proposed a model of increased stage CIC filter
and FFT for channelizer.
For designing model sim altera is used for simulation
purpose and xilinz ISE is used for synthesis.
4. Basic architecture of channelizer
Discrete data's
Sequential
Integrator Decimator 8 point FFT
combination
CIC FILTER BLOCK
5. Cascaded Integrator-Comb
(CIC) Filter
Used to achieve arbitrary and large sample rate changes in
digital systems.
Used as decimation or interpolation filters.
Efficiently implemented without multipliers, utilizing only
adders and subtractors.
6. Single CIC filter block diagram
Z^-1 Z^M
+ -
+ + R + +
integrator decimator comb filter
7. Features
1-32-bit input data width.
1-8 cascaded stages.
1-4 cycles differential delay.
Run-time programmable for both decimation and
interpolation.
8. Cont…
2-16,384 decimation and interpolation sampling rate
factor.
Multi-channel (up to 4 channels) support for both
decimation and interpolation.
Fully synchronous, single-clock design.
9. Integrator
An integrator is a single-pole IIR filter .
with a unity feedback coefficient.
operating at a higher sampling rate, fS.
10. Comb filter
A comb is a FIR filter .
with M unity differential delays .
operating at a lower sampling rate.
11. Fast Fourier transform
An efficient algorithm to compute the discrete Fourier
transform (DFT) and its inverse.
An FFT computes the DFT and produces exactly the
same result as evaluating the DFT.
Difference is that an FFT is much faster.
DFT of N points takes O(N 2) arithmetical operations,
FFT take only O(N log N) operations.
12. What is Software Defined
Radio?
A collection of hardware and software technologies.
Radio in which some or all of the physical layer functions
are software defined.
Radio’s operating functions are implemented through
modifiable software or firmware .
Operating on programmable processing technologies.
13. Benefits of SDR
For Radio Equipment Manufacturers and System
Integrators.
For Radio Service Providers.
For End Users - from business travelers to soldiers on the
battlefield.
14. Field programmable gate array
An integrated circuit designed to be configured by the
customer or designer after manufacturing.
Configuration is generally specified using a hardware
description language (HDL).
Contain programmable logic components called "logic
blocks“.
Hierarchy of reconfigurable interconnects that allow the
blocks to be "wired together“.
15. FPGA design and programming
The HDL form is suited to work with large structures .
It's possible to just specify numerically rather than having
to draw every piece by hand.
Electronic design automation tool is used and technology-
mapped netlist is generated.
The netlist can then be fitted to the actual FPGA
architecture using a process called place-and-route.
16. Conti…
The user will validate the map, place and route results
Once the design and validation process is complete
The binary file generated is used to reconfigure the FPGA.
17. Proposed design of
channelizer
5 stage integrator and 5 stage comb filter with one
decimator .
To increase efficiency totally there are 8 complete stages
of CIC.
An 8 point FFT block.
18. Architecture of our design
Deci val
data
clk
xin x0 out0
Stage 1
reset
x1 out1
Stage 2
Stage 3 x2 x1 out2
x3 out3
Stage 4
8 point FFT
Stage 5
Stage 6
Stage 7
x7 out7
Stage 8
CIC FILTER BLOCK
19. Individual CIC filter of our
design
I1 I2 I3 I4 I5 R C1 C2 C3 C4 C5
Where
I1,I2,I3,I4,I5 are integrator
R is decimator
C1,C2,C3,C4,C5 are comb filter
20. Sample coding of integrator
else
For integrator section
begin
always @(posedge clk)
x<=xin;
begin
rst1<=1'b1;
if(~rst)
i0<=i0+sxtx;
begin
integrator 1
i0<=26'd0;
i1<=i1+i0;
i1<=26'd0;
integrator 2
i2<=26'd0;
i2<=i2+i1;
i3<=26'd0;
integrator 3
i4<=26'd0;
i3<=i3+i2;
rst1<=1'b0;
integrator 4
end
i4<=i4+i3;
integrator 5
end
27. CONCLUSION
Efficiency in terms of architecture optimizations such as
those made in the Polyphase FFT.
Implementation aspects leading to smaller area, low
power, radiation hardness and low cost seem very
promising.
The designed channelizer can be utilized in real time SDR
channel.
There is promising decrease in noise by the design.
28. REFERENCES
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