page_title: Software-defined radio
section_title: Amateur and home use
hierarchical_section_title: Software-defined radio / Amateur and home use
caption_attribution_description: Perseus SDR (software defined radio) by Microtelecom, covering 10 kHz - 30 MHz.
context_page_description: Software-defined radio is a radio communication system where components that have been traditionally implemented in hardware are instead implemented by means of software on a personal computer or embedded system. While 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 personal 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. Such a design produces a radio which can receive and transmit widely different radio protocols 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 the SDRForum to become the dominant technology in radio communications.
context_section_description: A typical amateur software radio uses 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 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 efforts use 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, 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 the Flex Radio, 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 the Quadrus coherent multi-channel SDR receiver for short wave or VHF/UHF in direct digital mode of operation.
caption: Microtelecom Perseus - a HF SDR for the amateur radio market
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