Single-channel Cable Modulator

Overview

The CMS0021 Single-channel Cable Modulator encodes a transport stream for J83 or DVB-C. The resulting QAM-symbols are filtered and up-converted for output to the radio interface as a single I/Q sample stream for translation to the final RF frequency.

Although most designs will implement only one of the cable standards, it is possible to synthesise the core to support any combination of standards in a single device.

Multiple instances of CMS0021 may be used on an FPGA, sharing access to a single external RAM device. This would typically take the form of a fast SRAM (or possibly SDRAM through a suitable SDRAM controller).

Multi-core implementations typically employ separate DACs for each core with the resulting modulated baseband or IF carriers up-converted to the assigned RF frequency bands and combined to produce the wideband cable transmission signal.

Key Features

Compliant with DVB-C (EN 300 429); ITU J.83 Annexes A, B and C; DOCSIS 1.x, 2.0 and 3.0.
Scalable architecture supports multiple instances per FPGA.
Modulation accuracy > 45dB (MER).
On-chip or off-chip interleaving RAM.
Variable symbol-rate interpolation.
Software selectable channel filter.
AD9857/AD9957/AD9789 interface and auto programming support.
AD9516/ADF4350 PLL programming support.
Extension core available for SPI/ASI interface with integrated PCR TS re-stamping, NULL TS packet removal/filtering and NULL/PRBS TS packet insertion.
Seamless integration with Altera ASI megacore when using SPI/ASI extension core.
Optional input and output TS rate estimation registers.
Optional noise interference source
Modes that are not required may be removed with synthesis options to generate a compact, efficient design.
Designed for very efficient FPGA implementation without compromise to the targeting of gate array or standard cell structures such as Altera HardCopy.
Supplied as a protected bitstream or netlist (Megacore for Altera FPGA targets).

Block Diagram

Deliverables

Optimised for Xilinx and Altera.
Evaluation boards available

Technical Specifications

Availability

Now

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