BCM3037 - QAMlink® Upstream Burst Modulator

QAMlink® Upstream 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.

The BCM3037 accepts a serial data stream and transmit control inputs. The output consists of an analog modulated and filtered data burst containing data at variable symbol rates and three modulation formats, which are π/4 DQPSK, QPSK and 16-QAM. Modulation can include differential or non-differential encoding. The modulated burst consists of a power up, ramp up, preamble, data, FEC, ramp down, guard time and power down in each burst. The output of the BCM3037 can then be sent to a power amplifier. There are standard DAVIC A0 and ATM UTOPIA serial input interfaces provided. There is also a generic byte-based interface. Alternatively, the BCM3037 can be configured to provide a data bit clock for synchronizing data. Control information is input through either an I2C-compatible or SPI-compatible serial interface.

  • The Broadcom BCM3037 is a universal QPSK/QAM burst transmitter for DOCSIS/EuroDOCSIS applications
  • DOCSIS/EuroDOCSIS, IEEE 802.14, DAVIC and DVB-compliant
  • A high-performance, integrated solution for upstream modulation in cable data modems, interactive cable-TV set-top boxes, and wireless applications
  • Significantly increases upstream channel bandwidth