QAMLINK® UNIVERSAL BURST MODULATOR

The BCM3037 provides a complete π/4 DQPSK, QPSK and 16-QAM Upstream Burst Modulator and FEC encoder integrated on a single chip. A burst FIFO buffer provides input data rate decoupling. The FEC encoder consists of a programmable randomizer and a programmable RS encoder. There is also a programmable preamble prepend, programmable symbol mapper, and a programmable transmitter preequalizer. The modulator consists of dual square-root raised cosine filters with programmable excess bandwidth, α=0.25 or α=0.50, interpolation filters, and a digital upconverter which translates the shaped pulse to a digitally tunable IF center frequency. An integrated 10-bit DAC then converts this signal to an analog waveform with programmable attenuation.

FEATURES
• The Broadcom BCM3037 is a universal QPSK/QAM burst transmitter for DOCSIS/EuroDOCSIS applications
• DOCSIS/EuroDOCSIS, IEEE 802.14, DAVIC and DVBcompliant
• Programmable Modulation: π/4 DQPSK, QPSK, 16-QAM
• Variable symbol rates up to 6.25 MB
• 25 Mbps maximum data rate
• QAMLink modulator with α = 0.25/0.50 square-root Nyquist filters
• Digitally tunable IF center frequency up to 65 MHz
• Programmable Components Include:
   • 6 burst profiles
   • Analog output attenuation up to 25dB
   • Transmitter pre-equalizer
   • RS encoder, GF (256), T = 0 to 10
   • Last RS codeword: fixed length, shortened
   • 23-bit randomizer: polynomial, seed, type
   • Differential/non-differential encoding
• Integrated 10-bit digital-to-analog converter
• Direct interface to BCM3250 MAC
• JTAG Test Interface
• 64-pin PQFP Package