BCM3037

Description

The BCM3037 provides a complete /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, =0.25 or =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 of BCM3037 consists of an analog modulated and filtered data burst containing data at variable symbol rates and three modulation formats, which are /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.