Until recently, most radios have used the superheterodyne (superhet) receiver, however enhancements in semiconductor technology have enabled the integration of DCRx, allowing it to become the technology of choice for radio receivers in many applications.
A DCRx mixes the required RF signal down to 0Hz in a single quadrature mixing process using a local oscillator (LO) tuned to the wanted RF channel frequency.
Selectivity filtering and gain can now take place at baseband with practical, low power, analogue and digital circuits. DCRx also eliminates the need for an image-reject filter.
Key features of the CMX994 include on-chip VCO for VHF applications, precision baseband filtering with selectable bandwidths and the smallest PCB area, typically less than 50% of a dual superhet. Another important feature is the single ended RF connections, which eliminate the need for baluns.
The CMX994 operates at 3.0 – 3.6 V, and comes in a Q4 40-pin VQFN package.