The two most computation and resource intensive tasks in the design of receiver for software defined radio sdr are sample rate conversion src and channelization. The ddc performs the frequency translation necessary to convert the high input sample rates found in a digital radio, down to lower sample rates for further and easier processing. Source material recorded with one sample rate often must be converted to another sample rate for processing. Software defined radio sdr technology enables such functionality in wireless devices by using a reconfigurable hardware platform across multiple standards. Area efficient fractional sample rate conversion architecture for software defined radios 978 the algorithms used in these applications use multi rate signal processing techniques. Optimal design and simulation for multirate symbol timing. Sample rate conversion filter design for multistandard. Building a software defined radio sdr involves many trades offs. This paper details a software implementation of a sampling rate conversion algorithm which is particularly efficient at converting multiple audio channels. As the efficient implementation of multi rate systems on fpga heavily depends on architecture. Highspeed data converters make directsampling receivers. About usrp bandwidths and sampling rates ettus knowledge base.
Bachelor thesis sample rate conversion in digital signal. Designed for lowcost experimentation, it combines the ad9361 rfic direct conversion transceiver providing up to 56mhz of realtime bandwidth, an open and reprogrammable spartan6 fpga, and fast superspeed. Bachelor thesis sample rate conversion in digital signal processors conducted at the signal processing and speech communications laboratory graz university of technology, austria by marian forster, 1031275 supervisor. The article describes a fieldprogrammable gate array fpga circuit for arbitraryratio resampling of signals in the low frequency to very high frequency bands, intended for software defined radio applications. If the desired sampling rate is not directly supported by the hardware, then it will be necessary to re sample in software. The standard fpga rmware provides two digital downconverters ddc. Lagranges polynomial based farrow filter implementation.
For example, the fpga of the usrp x300x310 sends and receives samples at 200 mss from the dacs and adcs respectively. Abstract this paper deals with the implementation of the sample rate conversion subsystems of the digital frontend, at intermediate frequency if, and of a synchronization subsystem in the framework of a software radio receiving terminal. A fractional sample rate conversion filter for a software. Rethinking the multichannel ddc the software radio market generates a growing number of requests for ddc solutions with densities higher than the 16 or 32 channels provided per board using asics or standard fpga designs. Pushing beyond the superheterodyne, directsampling receivers can help meet the demands of todays communications systems, but they need ultrafast adcs to make. Sdr is a popular prototyping platform for wireless communication systems due to its flexibility and utility. Universal software radio peripheral usrp is a range of software defined radios designed and sold by ettus research and its parent company, national instruments. Altera corporation 1 march 2004 preliminary application note farrowbased decimating sample rate converter introduction the farrowbased decimating sample rate converter demonstrates a farrow resampler. This paper reports on the design and implementation of an opensource library of parameterizable and reusable hardware description language hdl intellectual property ip cores designed for the development of software defined radio sdr applications that are deployed on fpga based reconfigurable computing platforms.
Modelbased design for software defined radio on an fpga. Nov 07, 2011 lattice xp25 fpga for sample rate conversion. Overview overview the usrp b210 provides a fully integrated, singleboard, universal software radio peripheral usrp platform with continuous frequency coverage from 70 mhz 6 ghz. When implementing these modules, generated spurious harmonics and limited hardware resource problems can be critical.
With the recent advances in fpga technology, the more. Fpga implementation of high speed cic filter for software defined radio system asar international conference, coimbatore chapter 12th may 20, isbn. Hdl sample rate conversion using farrow filters matlab. At this point lets see how to interface an adc with single data rate sdr parallel output to an fpga. Farrowbased decimating sample rate converter application. Designed for lowcost experimentation, it combines the ad9361 rfic directconversion transceiver providing up to 56mhz of realtime bandwidth, an open and reprogrammable spartan6 fpga, and fast superspeed usb 3. Request pdf fpga based implementation of efficient sample rate conversion for software defined radios software radio is a burgeoning application in the domain of wireless communications. Fpga implementation of a multimodal sample rate converter and. This is not necessarily correlated with the sample rate.
Digital down converter ddc are used as sample rate converters. A recently proposed architecture is adopted and optimized for the realization. Worth noting that she actually uses the fpga for signal processing later on. In the first nyquist region, we can easily cover the long wave, medium wave and short. Our hypothesis is to have a timing diagram like the figure3 above, i. Design and implementation of digital signal processing hardware for a software radio reciever by jake talbot a report submitted in partial ful. How to specify sample rates for xilinx zynqbased radio. Software defined radio sdr seems to be a solution for communications for rapid changes in the communication standards. This effectively increases the resolution of the audio signal leaving roon.
Firstly, a practical factorization algorithm has been formulated that iteratively assigns rate change factors to filtering stages of a proposed multistandard src architecture. Prototyping a software defined radio receiver based on. A practical fpga based architecture for arbitraryratio sample rate conversion. Use a large sample rate to capture the entire chunk of spectrum perform down conversion of each subchannel in software disadvantage. Ideal for a wide range of markets and applications implementing the sample rate converter on a xilinx fpga offers a lowcost. This sets the hypothetical maximum digital bandwidth of a system based on the usrp. As such, it is not representative any more for all my sdr activities, which have continued since then, though mostly on the software. The fpga processing bandwidth is the sample rate provided by the adcs and dacs on the usrp motherboard. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Hello all, im looking for a vhdlverilog model for a sample rate converter, probably for fpga implementations.
On both models high sample rate processing, like digital up and down conversion, takes place in the fpga. For the purpose of this example, we will show how you can convert the sampling rate of an audio signal from 8khz to 44. This paper deals with the implementation of the sample rate conversion subsystems of the digital frontend, at intermediate frequency if, and of a synchronization subsystem in the framework of a software radio receiving terminal. The asynchronoussample rate converter src reference design addresses these conversion requirements by leveraging the unrivalled dsp horsepower of xilinx fpgas. Sample rate conversion for a software radio receiver is one of the critical tasks. Fpga technology fueling software defined radio signal.
Speedgoat fpga io modules offer the lowestlatency interconnections as well as support for hundreds of fast analog and digital io and tens of multigigabit transceivers to implement controls and plant simulation algorithms designed with simulink, and to process, monitor, tune, log, and replay analog, digital, or vision data. Sampling perhaps 80 mhz with a single adc directly into the computer would allow all the processing to be done in the computer where a gpu graphics adapter could do all the filtering and bandwidth reduction that is needed. Abstract the evolution towards applications with increasing functionalities leads to the need of high flexible systems that support a high number of different standards while decreasing the required hardware space. I am starting with lv and fpga and i am not sure about sampling. First, build the stipcores library with the simple makefile. Usrp b210 usb software defined radio sdr ettus research. Feb 15, 2014 fpga implementation of optimized cic filter for sample rate conversion in software radio receiver 1.
The asynchronous sample rate converter reference design addresses these conversion requirements by leveraging the unrivalled dsp horsepower of xilinx fpgas. From an introduction to software radio and a refresher on the fundamentals of sampling and sample rate conversion, to discussions on block signal processing and wellknown and novel structures for sample rate conversion, the book offers you practical guidance that enables you to quickly find solutions for your challenging projects in the field. Adc digital data present at adc output interface at rising edge adc digital clock. A recently proposed architecture is adopted and optimized for the realization of a. In this chapter, we propose a novel design of scalable and realtime data acquisition software architecture for software defined radio sdr using universal software radio peripheral usrp. In such systems, digitally implemented modules to interface analogtodigital converters with the rest of the system working at a different clock rate can be required. Sample rate selection, filter coefficients digitally controlled analog loop. In one case, there is used sequential diagram and in the first frame there is made clock or time delay to establish sample rate.
Sample rate conversion src between arbitrary factors is useful for many applications including symbol synchronizations in digital receivers, speech coding, audio sampling, etc. Roons sample rate converters use fully synchronous, polyphase interpolation. In this context, this paper presents a practical implementation of multistage sample rate conversion in multistandard software radios. Design and implementation of digital signal processing hardware for a software radio reciever by jake talbot, master of science. This only e ects the clock rate of the adcs, most of the sample rate conversion is done in the fpga. Hardware optimized sample rate conversion for software. A practical fpgabased architecture for arbitraryratio. Configuration and ft2232h pin breakout so i can experiment with usbbased fpga code updating. Sample rate conversion in software configurable radios tim. But one of the most fundamental is should you use an fpga or a cpu to do the processing. Due to the phenomenon of bandpass sampling, digitization of a very high intermediate frequency incorporating.
Software defined radio sdr omapl8based reference platform. Hardware optimized sample rate conversion for software defined radio. Design and implementation of sampling rate converters for. By basebanding in the fpga, we can baseband and filter digitally at the full sample rate, which. Initially a sample rate of 100mhz has been chosen, this gives 50mhz of rf bandwidth. Under this condition, the best clock edge should be the rising edge of adc output clock. A perviously proposed architecture is adopted and optimized for the realization of a multimodal terminal, the main operational mode of which is umts, but also. When implementing these modules, generated spurious harmonics and limited hardware resource problems.
This paper puts the main emphasis on analyzing the modeling and simulation by simulink of digital mixing converter part and cic decimation filter part of digital down converter and the realization on fpga. These are the important block in every digital communication system. I am going to try to explain my question with the examples from lv installation. Full support for the usrp hardware driver uhd software allows you to immediately begin.
Design and implementation of highperformance fpga signal processing datapaths for software defined radios chris h. This work includes complete design and subsequent implementation of sample rate conversion filters on a xilinx vertex ii pro fpga board. Hdl implementation of a digital downconverter for lte. Speedgoat fpga io modules, code modules, and simulink workflow. That means a rather complicated hardware and a high cost.
Though this setup worked well, it was insufficient for applications that require higher sample rates. Developed by a team led by matt ettus, the usrp product family is intended to be a comparatively inexpensive hardware platform for software radio, and is commonly used by research labs, universities, and hobbyists. In the context of sample rate conversion src filter design. Scripts for activating and deactivating the soundcard. The simulink modeling and fpga realization of digital down. The ddc filters have therefore been designed to suit this application. The algorithm works in simulation, but when trying to get it onto the fpga, ive got a problem with the sample rates. Carina schmidtknorreck, raymond knopp, and renaud pacalet. The inclusion of an integrated ddc digital down converter in the rf sampling adc allows the processing of one or more narrow band signals of interest with reduced decimated data rates at the ddc output and interface to the dsp fpga, while providing the observation of a large bandwidth via a high sample rate adc. The report presents an overview of different converter techniques as well as considers a suitable scheme with.
Audio sample rate converter reference design for xilinx fpgas. Basically, i want the fpga to work on a high rate preferably 960khz, but the exact rate is not important and then downsample the signal to a lower rate 48khz before sending it. Fpga implementation of optimized cic filter for sample. Audio sample rate converter reference designs for xilinx fpgas. Lakshmi 2 1 nit warangal department of ece, warangal, india email. For example software radio which should handle different conversion factors and standards. Software defined radio in fpga uses lvds io pins as 1bit adc dawsonjonfpga radio. Pa3fwms software defined radio page note added in 2017. Sharedmultiplier polyphase fir filter markus nentwig. This work focuses on the problem of designing and implement sampling rate converters for conversions between arbitrary sampling rates. This paper presents an approach of modelbased design for implementing a digital communication system on an fpga for software defined radio sdr. The software has been designed and tested in multithread model, using labview, which guarantees realtime performance and efficiency. Many digital systems for telecommunications are implemented via the software defined radio technique today. Fpga use in softwaredefined radios design and reuse.
With the proliferation of wireless standards, including wide area 3g, 2. Most people using the sample rate conversion features in roon will be performing upsampling, which is generally considered to provide an enhancement. Les if implemented in a field programmable gate array fpga. For a multistandard software radio with a very high intermediate frequencyif, which is of the order of 80mhz and above, the implementation of a sample rate converter is highly computationally intensive. After the signal is digitized, the data is sent to the fpga. Digital downconverters ddc is a key component of digital radios. Fpgabased implementation of efficient sample rate conversion. An optimized sample rate converter for a software radio. Abstract sample rate conversion src and channelization are the two necessary tasks to be implemented for the design of a radio receiver. Fpga, interpolating decimating fir filter, sample rate conversion, shared multiplexed pipelined multiplier discussion, working code parametrized verilog and matlab reference design for a fir polyphase resampler with arbitrary interpolation and decimation ratio, mapped to one multiplier and ram. The usrp n210 is powered by an fpga that offers 50% more resources than the usrp n200 enabling more complex code on the fpga to match the needs of demanding applications. Sep 18, 20 many digital systems for telecommunications are implemented via the software defined radio technique today.
Although no dac is needed in our alldigital transmitter, a sample rate converter src is still necessary to convert the sample rate to a fixed sample rate suitable for pwm generation. Optimal design and simulation for multi rate symbol timing recovery in software radio qpsk demodulation abstract. Design and implementation of highperformance fpga signal. Since this hardware is meant for a software radio system, making the hardware.
Second, import the main sdr control software into qtcreator and build. Initially a sample rate of 100mhz has been chosen, this gives 50mhz of rf. Software defined radio in fpga uses lvds io pins as 1bit adc dawsonjonfpgaradio. Jul 19, 2011 jeri ellsworth builds a software radio. Multichannel fractional sample rate conversion filter. Channelization we want to simultaneously process signals at multiple center frequencies using a single rf front end, this can be accomplished in a few ways option 1. About usrp bandwidths and sampling rates ettus knowledge.
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