The HSP50214B Programmable Downconverter converts
digitized IF data into filtered baseband data which can be
processed by a standard DSP microprocessor. The
Programmable Downconverter (PDC) performs down
conversion, decimation, narrowband low pass filtering, gain
scaling, resampling, and Cartesian to Polar coordinate
conversion.
The 14-bit sampled IF input is down converted to baseband
by digital mixers and a quadrature NCO, as shown in the
Block Diagram. A decimating (4 to 32) fifth order Cascaded
Integrator-Comb (CIC) filter can be applied to the data
before it is processed by up to 5 decimate-by-2 halfband
filters. The halfband filters are followed by a 255-tap
programmable FIR filter. The output data from the
programmable FIR filter is scaled by a digital AGC before
being re-sampled in a polyphase FIR filter. The output
section can provide seven types of data: Cartesian (I, Q),
polar (R, θ), filtered frequency (dθ/dt), Timing Error (TE), and
AGC level in either parallel or serial format.

Features
• Up to 65MSPS Front-End Processing Rates (CLKIN) and
55MHz Back-End Processing Rates (PROCCLK)
Clocks May Be Asynchronous
• Processing Capable of >100dB SFDR
• Up to 255-Tap Programmable FIR
• Overall Decimation Factor Ranging from 4 to 16384
• Output Samples Rates to ≅12.94MSPS with Output
Bandwidths to ≅ 982kHz Lowpass
• 32-Bit Programmable NCO for Channel Selection and
Carrier Tracking
• Digital Resampling Filter for Symbol Tracking Loops and
Incommensurate Sample-to-Output Clock Ratios
• Digital AGC with Programmable Limits and Slew Rate to
Optimize Output Signal Resolution; Fixed or Auto Gain
Adjust
• Serial, Parallel, and FIFO 16-Bit Output Modes
• Cartesian to Polar Converter and Frequency Discriminator
for AFC Loops and Demodulation of AM, FM, FSK, and
DPSK
• Input Level Detector for External I.F. AGC Support
• Pb-Free Plus Anneal Available (RoHS Compliant)

Applications
• Single Channel Digital Software Radio Receivers
• Base Station Rx’s: AMPS, NA TDMA, GSM, and CDMA
• Compatible with HSP50210 Digital Costas Loop for PSK
Reception
• Evaluation Platform Available