The GC4016 provides four digital receiver channels. Each channel digitally downconverts and filters signals of interest from wideband sources at sample rates up to 100 MSPS. In addition to providing four narrowband channels, the GC4016 can optionally provide four CDMA channels with 4x oversampling, two CDMA channels with 8x oversampling, or a single wideband 5 MHz bandwidth channel for 3rd generation UMTS/CDMA2000-3x systems.
Each GC4016 receiver channel features a digital oscillator, mixer, decimating filter, gain stage, and digital resampler. The digital resampler function permits output sample rates to be precisely specified independent of clock rate. This simplifies the design of multiple air interface standard basestations. Each channel may be programmed with a different bandwidth/rate.
GC4016 channel performance is outstanding, providing 115 dB of spurious free dynamic range. Signal data can be accepted in a variety of formats including floating point and LVDS signaling.
The chip's decimating filter down-samples the rate of the signal data by a factor from 32 to 16,384. The filter chain consists of a five stage CIC filter followed by two FIR filters. Both FIR filters can be user-programmed with custom coefficient sets over the control bus. Output data is available in serial, parallel, or link port formats. The GC4016's configuration parameters are programmed through an 8 bit microprocessor interface. Built-in circuitry permits synchronization of multiple chips. The GC4016 operates from a 2.5 volt core, 3.3 volt I/O power supply and is housed in a compact 160 ball 15mm × 15mm BGA package.