CMX7163 – QAM Modem

Product description

The CMX7163 QAM Modem is a low power half-duplex device supporting multiple channel spacings under host microcontroller (µC) control. Its Function Image (FI) is loaded to initialise the device and determine modulation types.

The 7163FI-4.x supports 4-QAM, 16-QAM, 32-QAM and 64-QAM modulations up to 96kbps in a 25kHz channel, with channel estimation and equalization to provide robust performance under realistic channel conditions.

Adaptive Coded Modulation (ACM) features allow modulation type and block format to be changed on the fly via over-air commands that control a receiving CMX7163. They enable a Tx host to select optimum modulation and coding per burst to suit application message size, link channel quality and can also relax required Rx host message parsing speed.

High performance digital IF filters may be reconfigured to support multiple channel spacing’s via host command. This feature may eliminate the need to switch between multiple discrete IF filters.

An integrated analogue interface supports ‘direct connection’ to zero IF I/Q radio transceivers with few external components; no external codecs are required.

Intelligent auxiliary ADC, DAC and GPIO subsystems perform valuable functions and minimise host interaction and host I/O resources. Two synthesised system clock generators develop clock signals for off-chip use.

The device utilises CML’s proprietary FirmASIC component technology. On-chip sub-systems are configured by a Function Image data file that is uploaded during device initialisation and defines the device’s function and feature set.

Features

• No DSP or Codecs required; simply upload
  modulation Function Image (FI)
• Automatic Gain Control
• QAM 7163 FI-4.x
  – 4/16/64 QAM up to 96kbps in 25kHz
  – FEC and raw (uncoded) modes
  – Two x frame sync detectors
  – Automatic frame sync detectors
  – Rx carrier frequency and phase correction
• High Performance I/Q Radio Analogue Interface
  – Tx and Rx: ‘Direct connect’ to zero IF tranceiver
  – Digital IF filter reconfigures for multiple RF channel spacings (Rx)
  – Deviation control without manual trim (Tx)
  – I/Q trims
• C-BUS host Serial Interface
• Read/write 128-byte FIFOs and data buffers streamline transfers and relax host service latency
• Auxiliary Functions
  – Autonomous RAMDAC sequencer
  – Four x 10-bit ADCs
  – ADC averaging and trip on high/low ‘watch’ modes
  – Four x GPIO
  – Sequence GPIO on Tx or Rx trigger
  – Start Tx on digital trigger input
• Master C-Bus/SPI Serial Interface
  – For external slave devices e.g. RF transceiver and synthesiser
  – Pass-through mode expands host C-BUS/SPI capacity

Design resources