Sonifex 24-Channel FM Radio Capture PCIe Card

The Sonifex 24-Channel FM Radio Capture PCIe Card is a radio capture card designed for simultaneous recording of multiple radio stations. The frequency of each station is set in software and its audio appears as a standard Windows audio input device. RDS decoding is also supported. The card uses a high-speed A/D converter to digitize the entire FM band. The Radcap achieves exceptionally low audio distortion through the use of linear phase filtering and mathematically precise FM demodulation and stereo decoding. FM demodulation and stereo decoding is done in FPGA fabric, while RDS decoding, if enabled, is performed in the driver using the host CPU's SSE-2 instruction set. This division of labor between the FPGA and driver allows greatest flexibility in catering for future baseband technologies while minimizing the CPU overhead of the card. A WDM driver for Windows XP (SP2 or later), Server 2003, Vista, Server 2008, Windows 7, Server 2008 R2, Windows 8 and Server 2012 is supplied as well as software for setting the tuner frequencies and monitoring the received audio. A programming API and DLL for software control and monitoring are also supplied. The card can be configured to operate in stereo, mono or paired mono (two mono stations combined on a 2-channel audio stream) modes. Multiple cards can be used in a single PC, subject to available CPU bandwidth. A utility called FMSpectrum is supplied. This displays the RF spectrum from 85MHz to 111MHz, using data from the card's front-end 256-point FFT and may be useful in selecting the best location for the antenna or resolving interference problems. The card is factory-configured for 24 stations, but may be expanded in the field for an additional charge.