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70-507: Today, TAPR no longer focuses on packet radio, but continues as a research and development oriented group offering kits, assembled products, and publications related to the intersection of amateur radio and digital technology. TAPR describes itself as "A community that provides leadership and resources to radio amateurs for the purpose of advancing the radio art." Current products and development activity relate to software-defined radio , GPS , APRS and time and frequency measurement . TAPR

140-429: A direct conversion receiver . Unlike direct conversion receivers of the more distant past, the mixer technologies used are based on the quadrature sampling detector and the quadrature sampling exciter. The receiver performance of this line of SDRs is directly related to the dynamic range of the analog-to-digital converters (ADCs) utilized. Radio frequency signals are down converted to the audio frequency band, which

210-422: A high-pass filter , which allows through components with frequencies above a specific frequency, and a low-pass filter , which allows through components with frequencies below a specific frequency. In digital signal processing , in which signals represented by digital numbers are processed by computer programs, a band-pass filter is a computer algorithm that performs the same function. The term band-pass filter

280-427: A low-pass filter with a high-pass filter . A bandpass signal is a signal containing a band of frequencies not adjacent to zero frequency, such as a signal that comes out of a bandpass filter. An ideal bandpass filter would have a completely flat passband: all frequencies within the passband would be passed to the output without amplification or attenuation, and would completely attenuate all frequencies outside

350-429: A "USAF competitive advantage". So instead, with USAF permission, in 1991, Mitola described the architecture principles without implementation details in a paper, "Software Radio: Survey, Critical Analysis and Future Directions" which became the first IEEE publication to employ the term in 1992. When Mitola presented the paper at the conference, Bob Prill of GEC Marconi began his presentation following Mitola with: "Joe

420-404: A design produces a radio which can receive and transmit widely different radio protocols (sometimes referred to as waveforms) based solely on the software used. Software radios have significant utility for the military and cell phone services, both of which must serve a wide variety of changing radio protocols in real time. In the long term, software-defined radios are expected by proponents like

490-530: A false cycle. The use of the nomenclature "ideal" implicitly involves a greatly fallacious assumption except on scarce occasions. Nevertheless, the use of the "ideal" filter remains common despite its limitations. Fortunately, band-pass filters are available that steer clear of such errors, adapt to the data series at hand, and yield more accurate assessments of the business cycle fluctuations in major economic series like Real GDP, Investment, and Consumption - as well as their sub-components. An early work, published in

560-492: A lot of digital signal processors ( Texas Instruments C40s). The transmitter had digital-to-analog converters on the PCI bus feeding an up converter (mixer) that led to a power amplifier and antenna. The very wide frequency range was divided into a few sub-bands with different analog radio technologies feeding the same analog to digital converters. This has since become a standard design scheme for wideband software radios. The goal

630-414: A new signal format in two weeks from a standing start, and demonstrate a radio into which multiple contractors could plug parts and software. The project was demonstrated at TF-XXI Advanced Warfighting Exercise , and demonstrated all of these goals in a non-production radio. There was some discontent with failure of these early software radios to adequately filter out of band emissions, to employ more than

700-610: A request for information from Bell South Wireless at the first meeting of the Modular Multifunction Information Transfer Systems (MMITS) forum in 1996 (in 1998 the name was changed to the Software Defined Radio Forum), organized by the USAF and DARPA around the commercialization of their SpeakEasy II program. Mitola objected to Blust's term, but finally accepted it as a pragmatic pathway towards

770-460: A selected range of frequencies to be heard or decoded, while preventing signals at unwanted frequencies from getting through. Signals at frequencies outside the band which the receiver is tuned at, can either saturate or damage the receiver. Additionally they can create unwanted mixing products that fall in band and interfere with the signal of interest. Wideband receivers are particularly susceptible to such interference. A bandpass filter also optimizes

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840-461: A true software-based transceiver. E-Systems Melpar sold the software radio idea to the US Air Force. Melpar built a prototype commanders' tactical terminal in 1990–1991 that employed Texas Instruments TMS320C30 processors and Harris Corporation digital receiver chip sets with digitally synthesized transmission. The Melpar prototype didn't last long because when E-Systems ECI Division manufactured

910-434: A wide passband. These are respectively referred to as narrow-band and wide-band filters. Bandpass filters are widely used in wireless transmitters and receivers. The main function of such a filter in a transmitter is to limit the bandwidth of the output signal to the band allocated for the transmission. This prevents the transmitter from interfering with other stations. In a receiver, a bandpass filter allows signals within

980-412: Is a stub . You can help Misplaced Pages by expanding it . Software-defined radio Software-defined radio ( SDR ) is a radio communication system where components that conventionally have been implemented in analog hardware (e.g. mixers , filters , amplifiers , modulators / demodulators , detectors , etc.) are instead implemented by means of software on a computer or embedded system . While

1050-541: Is a device that passes frequencies within a certain range and rejects ( attenuates ) frequencies outside that range. It is the inverse of a band-stop filter . In electronics and signal processing , a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its passband but blocks components with frequencies above or below this band. This contrasts with

1120-563: Is a supporter of the HPSDR (High Performance Software-Defined Radio) project which has developed a modular and extensible hardware platform for amateur and experimenter oriented software-defined radio . Together with the ARRL , TAPR sponsors an annual Digital Communications Conference. They are the creators of the TAPR Open Hardware License . This article related to amateur radio

1190-486: Is absolutely right about the theory of a software radio and we are building one." Prill gave a GEC Marconi paper on PAVE PILLAR, a SpeakEasy precursor. SpeakEasy, the military software radio was formulated by Wayne Bonser, then of Rome Air Development Center (RADC), now Rome Labs; by Alan Margulies of MITRE Rome, NY; and then Lt Beth Kaspar, the original DARPA SpeakEasy project manager and by others at Rome including Don Upmal. Although Mitola's IEEE publications resulted in

1260-439: Is also used for optical filters , sheets of colored material which allow through a specific band of light frequencies, commonly used in photography and theatre lighting, and acoustic filters which allow through sound waves of a specific band of frequencies. An example of an analogue electronic band-pass filter is an RLC circuit (a resistor – inductor – capacitor circuit ). These filters can also be created by combining

1330-521: Is being maintained at Osmocom . The HPSDR (High Performance Software Defined Radio) project uses a 16-bit 135 MSPS analog-to-digital converter that provides performance over the range 0 to 55 MHz comparable to that of a conventional analogue HF radio. The receiver will also operate in the VHF and UHF range using either mixer image or alias responses. Interface to a PC is provided by a USB 2.0 interface, although Ethernet could be used as well. The project

1400-715: Is called the beam-mass system. Ensemble of beam-mass systems can be transformed into a band pass filter when appropriate dimensions of beams and masses are chosen. Although the process of designing a mechanical band pass filter is advanced, further study and work are still required to design more flexible band pass filters to suit large frequency intervals. This mechanical band pass filter could be used on vibration sources with distinct peak-power frequencies. In neuroscience , visual cortical simple cells were first shown by David Hubel and Torsten Wiesel to have response properties that resemble Gabor filters , which are band-pass. In astronomy , band-pass filters are used to allow only

1470-448: Is inherently hampered by the fact that civilian users can more easily settle with a fixed architecture, optimized for a specific function, and as such more economical in mass market applications. Still, software defined radio's inherent flexibility can yield substantial benefits in the longer run, once the fixed costs of implementing it have gone down enough to overtake the cost of iterated redesign of purpose built systems. This then explains

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1540-433: Is modular and comprises a backplane onto which other boards plug in. This allows experimentation with new techniques and devices without the need to replace the entire set of boards. An exciter provides 1/2 W of RF over the same range or into the VHF and UHF range using image or alias outputs. WebSDR is a project initiated by Pieter-Tjerk de Boer providing access via browser to multiple SDR receivers worldwide covering

1610-749: Is now being used in areas such as wildlife tracking, radio astronomy, medical imaging research, and art. ELF 3 Hz/100 Mm 30 Hz/10 Mm SLF 30 Hz/10 Mm 300 Hz/1 Mm ULF 300 Hz/1 Mm 3 kHz/100 km VLF 3 kHz/100 km 30 kHz/10 km LF 30 kHz/10 km 300 kHz/1 km MF 300 kHz/1 km 3 MHz/100 m HF 3 MHz/100 m 30 MHz/10 m VHF 30 MHz/10 m 300 MHz/1 m UHF 300 MHz/1 m 3 GHz/100 mm SHF 3 GHz/100 mm 30 GHz/10 mm EHF 30 GHz/10 mm 300 GHz/1 mm Band-pass filter A band-pass filter or bandpass filter ( BPF )

1680-480: Is providing a flexible new approach to meet diverse soldier communications needs through software programmable radio technology. All functionality and expandability is built upon the SCA. The SCA, despite its military origin, is under evaluation by commercial radio vendors for applicability in their domains. The adoption of general-purpose SDR frameworks outside of military, intelligence, experimental and amateur uses, however,

1750-460: Is sampled by a high performance audio frequency ADC. First generation SDRs used a 44 kHz PC sound card to provide ADC functionality. The newer software defined radios use embedded high performance ADCs that provide higher dynamic range and are more resistant to noise and RF interference. A fast PC performs the digital signal processing (DSP) operations using software specific for the radio hardware. Several software radio implementations use

1820-457: Is the use of bandpass filters to extract the business cycle component in economic time series. This reveals more clearly the expansions and contractions in economic activity that dominate the lives of the public and the performance of diverse firms, and therefore is of interest to a wide audience of economists and policy-makers, among others. Economic data usually has quite different statistical properties than data in say, electrical engineering. It

1890-439: Is very common for a researcher to directly carry over traditional methods such as the "ideal" filter, which has a perfectly sharp gain function in the frequency domain. However, in doing so, substantial problems can arise that can cause distortions and make the filter output extremely misleading. As a poignant and simple case, the use of an "ideal" filter on white noise (which could represent for example stock price changes) creates

1960-412: Is very low when covering the 4G and 5G spectrum , while providing good return loss and group delay . Energy scavengers are devices that search for energy from the environment efficiently. Band pass filters can be implemented to energy scavengers by converting energy generated from vibration into electric energy. The band pass filter designed by Shahruz (2005), is an ensemble of cantilever beams, which

2030-503: The 4G and 5G wireless communication applications respectively. It is developed and extended from 3-pole single-band band pass filter, where an additional resonator is applied to a 3-pole single-band band pass filter. The advanced band pass filter has a compact size with a simple structure, which is convenient for implementation. Moreover, the stop band rejection and selectivity present a good performance in RF noise suppression. Insertion loss

2100-673: The DREAM open-source project decodes the COFDM technique used by Digital Radio Mondiale . There is a broad range of hardware solutions for radio amateurs and home use. There are professional-grade transceiver solutions, e.g. the Zeus ZS-1 or FlexRadio, home-brew solutions, e.g. PicAStar transceiver, the SoftRock SDR kit, and starter or professional receiver solutions, e.g. the FiFi SDR for shortwave, or

2170-571: The IEEE Communications Magazine with the cover "Software Radio" was regarded as a watershed event with thousands of academic citations. Mitola was introduced by Joao da Silva in 1997 at the First International Conference on Software Radio as "godfather" of software radio in no small part for his willingness to share such a valuable technology "in the public interest". Perhaps the first software-based radio transceiver

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2240-402: The PCI computer bus to each other with a layered protocol. As a military project, the radio strongly distinguished "red" (unsecured secret data) and "black" (cryptographically-secured data). The project was the first known to use FPGAs (field programmable gate arrays) for digital processing of radio data. The time to reprogram these was an issue limiting application of the radio. Today,

2310-518: The Wireless Innovation Forum to become the dominant technology in radio communications. SDRs, along with software defined antennas are the enablers of cognitive radio . Superheterodyne receivers use a VFO ( variable-frequency oscillator ), mixer , and filter to tune the desired signal to a common IF ( intermediate frequency ) or baseband . Typically in SDR, this signal is then sampled by

2380-413: The modem functions, "key processing" and "cryptographic processing" managed the cryptographic functions, a "multimedia" module did voice processing, a "human interface" provided local or remote controls, there was a "routing" module for network services, and a "control" module to keep it all straight. The modules are said to communicate without a central operating system. Instead, they send messages over

2450-526: The DoD integrated process team (IPT) for programmable modular communications systems (PMCS) to proceed with what became the Joint Tactical Radio System (JTRS). The basic arrangement of the radio receiver used an antenna feeding an amplifier and down-converter (see Frequency mixer ) feeding an automatic gain control , which fed an analog-to-digital converter that was on a computer VMEbus with

2520-627: The Gold Room at TRW in California created a software baseband analysis tool called Midas, which had its operation defined in software. In 1982, while working under a US Department of Defense contract at RCA , Ulrich L. Rohde 's department developed the first SDR, which used the COSMAC (Complementary Symmetry Monolithic Array Computer) chip. Rohde was the first to present on this topic with his February 1984 talk, "Digital HF Radio: A Sampling of Techniques" at

2590-688: The Quadrus coherent multi-channel SDR receiver for short wave or VHF/UHF in direct digital mode of operation. Eric Fry discovered that some common low-cost DVB-T USB dongles with the Realtek RTL2832U controller and tuner, e.g. the Elonics E4000 or the Rafael Micro R820T, can be used as a wide-band (3 MHz) SDR receiver. Experiments proved the capability of this setup to analyze Perseids meteor shower using Graves radar signals. This project

2660-574: The Review of Economics and Statistics in 2003, more effectively handles the kind of data (stochastic rather than deterministic) arising in macroeconomics. In this paper entitled "General Model-Based Filters for Extracting Trends and Cycles in Economic Time Series", Andrew Harvey and Thomas Trimbur develop a class of adaptive band pass filters. These have been successfully applied in various situations involving business cycle movements in myriad nations in

2730-700: The Third International Conference on HF Communication Systems and Techniques in London. In 1984, a team at the Garland, Texas , Division of E-Systems Inc. (now Raytheon ) coined the term "software radio" to refer to a digital baseband receiver, as published in their E-Team company newsletter. A 'Software Radio Proof-of-Concept' laboratory was developed by the E-Systems team that popularized Software Radio within various government agencies. This 1984 Software Radio

2800-427: The analog-to-digital converter. However, in some applications it is not necessary to tune the signal to an intermediate frequency and the radio frequency signal is directly sampled by the analog-to-digital converter (after amplification). Real analog-to-digital converters lack the dynamic range to pick up sub-microvolt, nanowatt-power radio signals produced by an antenna. Therefore, a low-noise amplifier must precede

2870-441: The complete shortwave spectrum. De Boer has analyzed Chirp Transmitter signals using the coupled system of receivers. KiwiSDR is also a via-browser SDR like WebSDR. Unlike WebSDR, the frequency is limited to 3 Hz to 30 MHz ( ELF to HF ) On account of its increasing accessibility, with lower cost hardware, more software tools and documentation, the applications of SDR have expanded past their primary and historic use cases. SDR

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2940-498: The concept of SDR is not new, the rapidly evolving capabilities of digital electronics render practical many processes which were once only theoretically possible. A basic SDR system may consist of a computer equipped with a sound card , or other analog-to-digital converter , preceded by some form of RF front end . Significant amounts of signal processing are handed over to the general-purpose processor, rather than being done in special-purpose hardware ( electronic circuits ). Such

3010-403: The conversion step and this device introduces its own problems. For example, if spurious signals are present (which is typical), these compete with the desired signals within the amplifier's dynamic range . They may introduce distortion in the desired signals, or may block them completely. The standard solution is to put band-pass filters between the antenna and the amplifier, but these reduce

3080-415: The cutoff frequency, e.g., a shape factor of 2:1 at 30/3 dB means the bandwidth measured between frequencies at 30 dB attenuation is twice that measured between frequencies at 3 dB attenuation. A band-pass filter can be characterized by its Q factor . The Q -factor is the reciprocal of the fractional bandwidth . A high- Q filter will have a narrow passband and a low- Q filter will have

3150-441: The design of a filter seeks to make the roll-off as narrow as possible, thus allowing the filter to perform as close as possible to its intended design. Often, this is achieved at the expense of pass-band or stop-band ripple . The bandwidth of the filter is simply the difference between the upper and lower cutoff frequencies . The shape factor is the ratio of bandwidths measured using two different attenuation values to determine

3220-450: The designs of experimenting the band pass filter to achieve low insertion loss with a compact size. The necessity of adopting asymmetric frequency response is in behalf of reducing the number of resonators , insertion loss , size and cost of circuit production. 4-pole cross-coupled band pass filter is designed by Hussaini et al.(2015). This band pass filter is designed to cover the 2.5-2.6  GHz and 3.4-3.7  GHz spectrum for

3290-517: The first limited production units, they decided to "throw out those useless C30 boards", replacing them with conventional RF filtering on transmit and receive and reverting to a digital baseband radio instead of the SpeakEasy like IF ADC/DACs of Mitola's prototype. The Air Force would not let Mitola publish the technical details of that prototype, nor would they let Diane Wasserman publish related software life cycle lessons learned because they regarded it as

3360-478: The ideal software radio. Although the concept was first implemented with an IF ADC in the early 1990s, software-defined radios have their origins in the U.S. and European defense sectors of the late 1970s (for example, Walter Tuttlebee described a VLF radio that used an ADC and an 8085 microprocessor ), about a year after the First International Conference in Brussels. One of the first public software radio initiatives

3430-608: The increasing commercial interest in the technology. SCA-based infrastructure software and rapid development tools for SDR education and research are provided by the Open Source SCA Implementation ;– Embedded (OSSIE ) project. The Wireless Innovation Forum funded the SCA Reference Implementation project, an open source implementation of the SCA specification. ( SCARI ) can be downloaded for free. A typical amateur software radio uses

3500-463: The international economy. Band pass filters can be implemented in 4G and 5G wireless communication systems . Hussaini et al.(2015) stated that, in the application of wireless communication , radio frequency noise is a major concern. In the current development of 5G technology, planer band pass filters are used to suppress RF noises and removing unwanted signals . Combine, hairpin, parallel-coupled line, step impedance and stub impedance are

3570-530: The largest global footprint for software radio, Mitola privately credits that DoD lab of the 1970s with its leaders Carl, Dave, and John with inventing the digital receiver technology on which he based software radio once it was possible to transmit via software. A few months after the National Telesystems Conference 1992, in an E-Systems corporate program review, a vice-president of E-Systems Garland Division objected to Melpar's (Mitola's) use of

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3640-515: The open source SDR library DttSP. The SDR software performs all of the demodulation, filtering (both radio frequency and audio frequency), and signal enhancement (equalization and binaural presentation). Uses include every common amateur modulation: morse code , single-sideband modulation , frequency modulation , amplitude modulation , and a variety of digital modes such as radioteletype , slow-scan television , and packet radio . Amateurs also experiment with new modulation methods: for instance,

3710-412: The passband. In practice, no bandpass filter is ideal. The filter does not attenuate all frequencies outside the desired frequency range completely; in particular, there is a region just outside the intended passband where frequencies are attenuated, but not rejected. This is known as the filter roll-off , and it is usually expressed in dB of attenuation per octave or decade of frequency. Generally,

3780-513: The ports may generally be replaced by passive radiators if desired. An eighth order bandpass box is another variation which also has a narrow frequency range. They are often used in sound pressure level competitions, in which case a bass tone of a specific frequency would be used versus anything musical. They are complicated to build and must be done quite precisely in order to perform nearly as intended. Bandpass filters can also be used outside of engineering-related disciplines. A leading example

3850-521: The radiation from the front surface of the cone is into a ported chamber. This modifies the resonance of the driver. In its simplest form a compound enclosure has two chambers. The dividing wall between the chambers holds the driver; typically only one chamber is ported. If the enclosure on each side of the woofer has a port in it then the enclosure yields a 6th order band-pass response. These are considerably harder to design and tend to be very sensitive to driver characteristics. As in other reflex enclosures,

3920-454: The radio filling the back of a truck. By the late 2000s, the emergence of RF CMOS technology made it practical to scale down an entire SDR system onto a single mixed-signal system-on-a-chip , which Broadcom demonstrated with the BCM21551 processor in 2007. The Broadcom BCM21551 has practical commercial applications, for use in 3G mobile phones . The Joint Tactical Radio System (JTRS)

3990-443: The radio's flexibility. Real software radios often have two or three analog channel filters with different bandwidths that are switched in and out. The flexibility of SDR allows for dynamic spectrum usage, alleviating the need to statically assign the scarce spectral resources to a single fixed service. In 1970, a researcher at a United States Department of Defense laboratory coined the term "digital receiver". A laboratory called

4060-418: The signal-to-noise ratio and sensitivity of a receiver. In both transmitting and receiving applications, well-designed bandpass filters, having the optimum bandwidth for the mode and speed of communication being used, maximize the number of signal transmitters that can exist in a system, while minimizing the interference or competition among signals. Outside of electronics and signal processing, one example of

4130-463: The simplest of interoperable modes of the existing radios, and to lose connectivity or crash unexpectedly. Its cryptographic processor could not change context fast enough to keep several radio conversations on the air at once. Its software architecture, though practical enough, bore no resemblance to any other. The SpeakEasy architecture was refined at the MMITS Forum between 1996 and 1999 and inspired

4200-684: The term "DigiCeiver" for their new range of DSP-based tuners with Sharx in car radios such as the Modena & Lausanne RD 148. From 1990 to 1995, the goal of the SpeakEasy program was to demonstrate a radio for the U.S. Air Force tactical ground air control party that could operate from 2 MHz to 2 GHz , and thus could interoperate with ground force radios (frequency-agile VHF , FM , and SINCGARS ), Air Force radios (VHF AM ), Naval Radios (VHF AM and HF SSB teleprinters ) and satellites ( microwave QAM ). Some particular goals were to provide

4270-539: The term "software radio" without credit to Garland. Alan Jackson, Melpar VP of marketing at that time, asked the Garland VP if their laboratory or devices included transmitters. The Garland VP said: "No, of course not — ours is a software radio receiver." Al replied: "Then it's a digital receiver but without a transmitter, it's not a software radio." Corporate leadership agreed with Al, so the publication stood. Many amateur radio operators and HF radio engineers had realized

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4340-468: The time to write a program for an FPGA is still significant, but the time to download a stored FPGA program is around 20 milliseconds. This means an SDR could change transmission protocols and frequencies in one fiftieth of a second, probably not an intolerable interruption for that task. The SpeakEasy SDR system in the 1994 uses a Texas Instruments TMS320C30 CMOS digital signal processor (DSP), along with several hundred integrated circuit chips, with

4410-412: The use of band-pass filters is in the atmospheric sciences . It is common to band-pass filter recent meteorological data with a period range of, for example, 3 to 10 days, so that only cyclones remain as fluctuations in the data fields. A 4th order electrical bandpass filter can be simulated by a vented box in which the contribution from the rear face of the driver cone is trapped in a sealed box, and

4480-637: The value of digitizing HF at RF and of processing it with Texas Instruments TI C30 digital signal processors (DSPs) and their precursors during the 1980s and early 1990s. Radio engineers at Roke Manor in the UK and at an organization in Germany had recognized the benefits of ADC at the RF in parallel. Mitola's publication of software radio in the IEEE opened the concept to the broad community of radio engineers. His May 1995 special issue of

4550-469: Was a digital baseband receiver that provided programmable interference cancellation and demodulation for broadband signals, typically with thousands of adaptive filter taps, using multiple array processors accessing shared memory. In 1991, Joe Mitola independently reinvented the term software radio for a plan to build a GSM base station that would combine Ferdensi's digital receiver with E-Systems Melpar's digitally controlled communications jammers for

4620-562: Was a program of the US military to produce radios that provide flexible and interoperable communications. Examples of radio terminals that require support include hand-held, vehicular, airborne and dismounted radios, as well as base-stations (fixed and maritime). This goal is achieved through the use of SDR systems based on an internationally endorsed open Software Communications Architecture (SCA). This standard uses CORBA on POSIX operating systems to coordinate various software modules. The program

4690-578: Was designed and implemented by Peter Hoeher and Helmuth Lang at the German Aerospace Research Establishment ( DLR , formerly DFVLR ) in Oberpfaffenhofen , Germany, in 1988. Both transmitter and receiver of an adaptive digital satellite modem were implemented according to the principles of a software radio, and a flexible hardware periphery was proposed. In 1995, Stephen Blust coined the term "software defined radio", publishing

4760-451: Was so successful that further development was halted, and the radio went into production with only a 4 MHz to 400 MHz range. The software architecture identified standard interfaces for different modules of the radio: "radio frequency control" to manage the analog parts of the radio, "modem control" managed resources for modulation and demodulation schemes (FM, AM, SSB, QAM, etc.), "waveform processing" modules actually performed

4830-506: Was the U.S. DARPA-Air Force military project named SpeakEasy . The primary goal of the SpeakEasy project was to use programmable processing to emulate more than 10 existing military radios, operating in frequency bands between 2 and 2000 MHz . Another SpeakEasy design goal was to be able to easily incorporate new coding and modulation standards in the future, so that military communications can keep pace with advances in coding and modulation techniques. In 1997, Blaupunkt introduced

4900-404: Was to get a more quickly reconfigurable architecture, i.e. , several conversations at once, in an open software architecture, with cross-channel connectivity (the radio can "bridge" different radio protocols). The secondary goals were to make it smaller, cheaper, and weigh less. The project produced a demonstration radio only fifteen months into a three-year research project. This demonstration

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