Undersampling in software defined radio

A group of nearly talented radio amateurs and short wave listeners have been working on a high performance software defined radio hpsdr project with the goal of ceating the sort of direct sampling sdr under discussion here. Undersampling figure 5 sampling figure 6 0 fs2 fs 3fs2 2fs 5fs2 3fs 7fs2 zone 1 zone 2 zone 3 zone 4 zone 5 zone 6 zone 7 no signal energy undersampling allows us to. Rf direct orthogonal phase undersampling technique for software defined radio article in electronics letters 4418. In software defined radio systems, placing the analogto digital converter adc near the antenna part in the block diagram of the receiver is. The colibriddc is a high performance direct sampling sdr, software defined radio covering all hf and 6 meter bands continuous from 9 khz to 55 mhz. A new rf quadrature undersampling technique for an ideal softwaredefined radio system.

An introduction to software defined radio for microwave. When a signal is undersampled, its spectrum has overlapping. Software radio, undersampling, nyquist rate, radio receiver 1. Sdr software defined radio has revolutionized electronic systems for a variety of applications including communications, data acquisition and signal processing. Folded signals still fall on top of each other but now there is energy in only one sheet. These receivers will usually significantly outperform the more general purpose receivers shown above in terms of sensitivity, but they usually concentrate only on the hf or amateur bands. Important signals of this sort include a radio s intermediatefrequency if, radio frequency rf signal, and the individual channels of a filter bank. We propose a quadrature undersampling technique that makes it possible to extract baseband inphase i and quadrature q data from an input rf signal directly.

Rfmicrowave engineers will find it clear and understandable because analogies will be made to conventional classic radio systems and components. As interest in sdr grows unabated and we continue to see ever more affordable hardware platforms, i thought it would be timely to roundup just a few of the things that it can be used for. Conventional direct conversion receivers softrock and similar typically use 16 bit soundcards which have a noise floor of about 2 bit and a real range of 14 bit. Experiment 22 undersampling in sdr software defined radio.

Evolution, like rust, never sleeps so expect the software radio laboratory people to further advance their. A softwaredefined radio for the masses, part 2 by gerald youngblood, ac5og come learn how to use a pc sound card to enter the wonderful world of digital signal processing. Defined radio sdr technology is the focus of much attention to realize such terminals 1, 2. Introduction to softwaredefined radio technical articles. Technical methodologies for sampling and undersampling. The most common definition is a radio in which some of the functions normally performed in hardware are done by. In case you would use the undersampling strategy at 20 mhz, sn would be 10 db smaller because the bandwidth ratio would be 10 times smaller. Systemlevel mitigation of undersampling adc nonlinearity. The highest n for which the condition is satisfied leads to the lowest possible sampling rates important signals of this sort include a radios intermediatefrequency if, radiofrequency rf signal, and the individual channels of a filter bank if n 1, then the conditions result in what is sometimes referred to as undersampling, bandpass sampling, or using a sampling rate less than the. This paper presents the advantages of the undersampling techniques in the digitalization of uhf signals. Typical applications are radio listening, ham radio, swl, radio astronomy, ndbhunting and spectrum analysis. Since different standards have different chipbit rates, noninteger samplerate conversion is required for sdr applications to convert the number of samples to an integer. All hdsdr program options can be stored and loaded per profile, to ease use of.

Off the shelf evaluation kits were used to explore how undersampling adcs work and how undersampling affects the demodulation of am waveforms. In signal processing, undersampling or bandpass sampling is a technique where one samples a bandpassfiltered signal at a sample rate below its nyquist rate. Highspeed data converters make directsampling receivers. The folks at pentek, who wrote the book on software radio, are pleased to announce their expanded software defined radio handbook. P art 1 gave a general description of digital signal processing dsp in software defined radios sdrs.

Multiband and multisignal receivers are investigated to realize such terminals. Over the last years ongoing advances in adc technology have enabled rf signals to be sampled at if frequencies. Undersampling figure 5 sampling figure 6 0 fs2 fs 3fs2 2fs 5fs2 3fs 7fs2 zone 1 zone 2 zone 3 zone 4 zone 5 zone 6 zone 7 no signal energy undersampling allows us to use aliasing to our. While the concept of sdr is not new, the rapidly evolving capabilities of digital electronics. Sdr sampling bandwidth do the bits per sample matter. Nov, 2014 an introduction to software defined radio for microwave engineers abstract.

Sep 26, 20 10 things you can do with software defined radio a look at just a small selection of the things that can be done using software defined radio. An uhf software defined reflectometer using undersampling. All hdsdr program options can be stored and loaded per profile, to ease use of different receivers. Softwaredefined radio sdr is a radio communication system where components that have been traditionally implemented in hardware e. Fm stereo receiver based on softwaredefined radio 1 jin li, 2 yijun luo, 3 mao tian 1,school of electronic information, wuhan university 430072, china, email.

Here, a novel, low cost, software defined approach for. In fact, the hpsdr group is creating hardware and software which greatly advances radio s state of the art. A software defined radio as in, the device itself is an rf communication system that incorporates a significant amount of this software based signal. The panoradio is a modern software defined radio receiver, that directly samples the antenna signal with 250 mhz with an analogtodigital converter. Then a small lows speed periodic nonuniform sampler was designed to act as a real time fm radio receiver.

A new rf quadrature undersampling technique for an ideal softwaredefined radio system abstract. Software defined radio sdr technology is the focus of much. This radio uses the fast convolution approach to filter and process the radio signals with the floating point microprocessor teensy 3. I have some dsp under my belt, though not a great deal. Jeffrey pawlan m 1989, sm 1996 has been a consultant as owner of pawlan communications for 25 years. P art 1 gave a general description of digital signal processing dsp in softwaredefined radios sdrs. Software defined radio sdr technology is the focus of much attention to realize such terminals 1, 2. Summary in software defined radio systems, placing the analogtodigital converter adc near the antenna part in the block diagram of the receiver is desired to improve the flexibility of the system. Experiment 22 undersampling in software defined radio 2007 emona instruments 225. This article provides a list of commercially available softwaredefined radio receivers. The receiver captures and displays signals from 0100 mhz, i.

Radio frequency reflectometry is widely used in nondestructive characterization of various materials and can also be applied to automatic impedance matching systems in telecommunication devices. Updated recently as its 11th edition, the handbook has proved to be a useful technical reference for engineers. This lecture will begin with the definition, history and evolution of software defined radio sdr. Undersampling is nowadays employed in softwaredefined radio or radar receivers and offers the possibility to relieve requirements in the analog receiver partition. Introduction as technology advances for personal mobile communications, making use of multiple communication services is desired at mobile terminals. Direct digitalization and frequency translation using. Direct sampling software defined radio is certainly where the bleeding edge is found, and the qs1r reflects that state of the art quite nicely. An uhf software defined reflectometer using undersampling downconversion in the adc abstract. Sdr sampling bandwidth amateur radio stack exchange. Prior to that, he had worked for many companies in california in very diverse areas of analog, rf, and microwave design and has been an engineer for 40 years.

New software defined radio sdrs products are popping up every few months these days so we thought wed compile a big list of available sdrs as there are a few people who were bitten by the rtlsdr bug and are now looking to upgrade. This section will cover the major aspects of a digital receiver design, suitable for use in a software defined radio application. The radio frequency rf sampling method, in which the received signal is. Many radio designers take full advantage of this undersampling technique for eliminating an entire analog frequency downconversion stage, thus saving board space, power, and money. In software defined radio systems, placing the analogtodigital converter adc near the antenna part in the block diagram of the receiver is desired to improve the flexibility of the system. A new rf quadrature undersampling technique for an ideal software defined radio system abstract. A software defined radio for the masses, part 2 by gerald youngblood, ac5og come learn how to use a pc sound card to enter the wonderful world of digital signal processing. This handbook shows how ddcs digital downconverters and ducs digital upconverters. Using software defined radio by pu and wyglinski artech house, 20. He has been designing rf and microwave hardware for software defined radio uses within instrumentation and military satellite communications since 1984. I am trying to learn some things about software defined radio sdr, so i figured i would start a hobby project to introduce myself to the topic. In case you would use the undersampling strategy at 20 mhz, s n would be 10 db smaller because the bandwidth ratio would be 10 times smaller. Here, a novel, low cost, software defined approach for measuring the reflection coefficient without using mixers or power detectors is. He has presented talks in a workshop at the 2010 ims in anaheim, the 2011 ims in baltimore, the 2012 ims in montreal, and also at chapter meetings and a short course.

Designed for the commercial, government, amateur radio and shortwave listener communities, this software provides a powerful interface for all sdr users. Multiband and multisignal receivers are investigated. Experiment 22 undersampling in sdr software defined. Introduction the current trend in radio systems is to reduce as much as possible the analog section of the transceiver and to implement as much as possible of the digital section in a programmable, reconfigurable manner 1. I want to undersample or bandpass sample, or whatever you want to call it rf signals, like amfm radio, and demodulate them. A practical guide to the wireless phyiscal layer the objective of this book is to provide a handson learning experience using sdr for engineering students and industry practitioners who are interested in mastering the design, implementation, and experimentation of a communication system.

Softwaredefined radio handbook lahden radioamatoorikerho. This application note describes oversampling and undersampling techniques. Greetings, i am trying to learn some things about software defined radio sdr, so i figured i would start a hobby project to introduce myself to the topic. Mtts distinguished microwave lecturer presentation.

Softwaredefined radio handbook 0 fs2 folded signals still fall on top of each other but now there is energy in only one sheet. Direct digitalization and frequency translation using an undersampling scheme for softwaredefinedradio based rfid uhfsystems by s. These i and q data are derived from three sampling points which lay in one cycle of the. Under sampling software defined radio sampling signal. Updated recently, the handbook has proved to be a useful technical reference for engineers. Softwaredefined radio for engineers analog devices. The radio frequency rf sampling method, in which the received signal is sampled at the rf stage, realizes such structure. For the past nine years he has been concentrating on software defined radio technology with his own radio designs including the development of very capable software and hardware. In case you would use the undersampling strategy at 20. If n 1, then the conditions result in what is sometimes referred to as undersampling, bandpass sampling, or using a sampling rate less than the nyquist rate 2f h. Here, a directsampling softwaredefined radio is using tis 12bit, 6. Fpga use in softwaredefined radios design and reuse. Undersampling rftodigital ct modulator with tunable.

An introduction to software defined radio for microwave engineers biography. Undersampling figure 5 samplingsamplingsampling figure 6 0 fs2 fs 3fs2 2fs 5fs2 3fs 7fs2 zone 1 zone 2 zone 3 zone 4 zone 5 zone 6 zone 7 no signal energy undersampling allows us to use aliasing to our. The folks at pentek, who wrote the book on software radio, are pleased to announce their expanded softwaredefined radio handbook. A new rf quadrature undersampling technique for an ideal software. For example, the db6nt transverter contains an lo at 10224mhz which is low side injection and makes the unwanted xband image response at 10080mhz. Resolved adc for undersampling data converters forum. Sdr softwaredefined radio has revolutionized electronic systems for a variety of applications including communications, data acquisition and signal processing.

A new rf quadrature undersampling technique for an ideal. The signal is not spectrally inverted in this case as can be seen from figure 3. Future generations of softwaredefinedradio sdr transceivers will perform most of the signal processing in the digital domain, thus allowing to increase the. Direct digitalization and frequency translation using an undersampling scheme for softwaredefinedradio based rfid uhfsystems. Rf direct orthogonal phase undersampling technique for. Implementation of a digital receiver engineering360. Bandpass sampling is an useful alternative to directly convert analog bandpass signals to digital signals without down conversion for software defined radio since a desired input signal to the. Software defined radio is a concept according to which rf communication is achieved by using software or firmware to perform signalprocessing tasks that are typically performed by hardware. Thus, it makes sense on as sdr to adjust the preamplifiers gain so that the noise. Software defined radio at 144mhz most ham transceivers at 1296mhz and higher use 2 meters as the if in order to make the rejection of the image frequency easier. Principles of sdr and fpgas role in software radio. Panoradio sdr panoradio sdr a standalone wideband 250 msps.

Experiment 22 undersampling in software defined radio 2007 emona instruments 223 certain sampling frequencies that will still cause aliasing and there is a. Radio amateurs and shortwave listening swling hobbyists have had high performance sdrs for some time now. The problem with the subject is that its so broad, its hard to simplify. Software defined radio sdr is a radio communication system where components that have been traditionally implemented in hardware e.