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Lit. No. M100V Rev. A 1/3/11
Chapter 2:
Raven M4x SNR Voter/Comparator Hardware Interface
A Raven M4x Blade can house up to 4 Raven-manufactured, DSP-based (digital signal processing)
communication modules (see Figure 1). The types of modules can be mixed and matched to tailor the M4x
system to a particular need. Raven Electronics manufactures a number of different types of modules to
interface to radios (or other 4-wire devices), 2- and 4-wire telephones, the public telephone network, and other
types of communications equipment. Each M4x Blade is a USB device that can accept commands from a host
computer. The host computer can also respond to different events that occur on a particular port.
A Raven M4x SNR Voter/Comparator generally uses either the Raven 476-150 or 476-151 4-wire E&M
modules. The 476-150 module has a 600 ohm, 300-3400Hz interface; the 476-151 has a 600 ohm or high
impedance input (software-selectable), a 600 ohm output, with a 5-3400Hz frequency range. The Raven 476-
150/151 4-wire E&M module is used to interface to 4-wire communication equipment. Each 476-150/151 4-
wire E&M module supports two ports of audio.
The main function of the 476-150/151 4-wire E&M module is to convert analog audio to the digital domain on
one end and back to analog on the other. Once the audio is converted to the digital domain, it can be bridged
with any other port in the system using the switching fabric provided by the backplane upon which the M4x
modules ride. The 476-150/151 4-wire module can also provide the following features via software commands
from the host computer:
•
Notch filtering
•
Level control
•
PTT generation (for radios)
•
COR detection (for radios)
•
Audio delay
•
Tone Detection (including DTMF and single tones)
•
Tone Generation (single tones, call progress tones, DTMF)
•
Signal-to-Noise Ratio Analysis for voting applications
Raven 476-150/151 4-Wire E&M Modules
