Raytheon SNV-12, Инструкция по установке и эксплуатации

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SNV-12 Operations Manual
4-4
4.5 Control Processor Module (CPM)
4.5.1 Features and Functions

Votes On Signal Quality Information (Noise or SNR) From SVM Modules

Control And Status Interface With SVM Modules

Voting System Expansion Control

RS-232 Remote Control/Programming

10/100 Ethernet Remote Control/Programming

Voting Transition Control

TX Steering And RX Group Control

Master CPM Controls Expansion CPMs In Expanded Systems
4.5.2 General
The unit's CPM Module controls the entire SNV-12. Via an internal high-speed serial bus, it
requests and receives SNR, Signal Quality, COR (signal present), speech present, and other
information from each Site Voter Module and votes the SVM with the best signal. It instructs
this SVM to output its audio to the voted audio bus. The CPM also provides an RS-232 serial
port allowing control and monitor of SNV-12 functions via an external computer or serially
interfaced console. The CPM-3 also provides a 10/100 Ethernet port for external control and
monitor functions as well as for software upgrades. The front panel of the CPM Module
contains a red Fault LED, along with three LEDs that indicate the Voting Status of an expanded
system, and one green LED to indicate network link status. The voting status LEDs are labeled
Master (Green), Expansion 1, and Expansion 2 (each yellow).
4.5.3 Hardware Description
The voter processors include a Freescale Coldfire based central control processor and up to 12
SVM modules. A synchronous serial bus supports inter-processor communications.
Each module has a unique "Select" line that is bi-directional. As far as the SVM module is
concerned the Select line is strictly an input, but the control processor (CPM) can both read and
write to these lines via a 74ACT16245 transceiver. If a module is not plugged in, the CPM will
read the Select line as TTL high (via a weak pull-up resistor). If an SVM module is plugged in,
it has a relatively strong pull-down resistor, and the CPM sees the input as TTL low. In this
fashion the CPM can not only "select" an SVM module, it can also quickly detect its presence
or absence.
The CPM interrogates each SVM module by first selecting the module, and then clocking out a
16 bit command word. While the command word is being clocked out, an SVM module status
word is being clocked in. The command word is used to give various commands to the SVM
module. One of the command word bits is used to "Vote" the SVM module. The status word,
read from the SVM module, contains 5 bits of Signal Quality data. The other 11 bits provide
SVM status information. See Table 6-1 for full details.
Once the CPM has polled each SVM module, it determines which module to "Vote" and
signals that module to place its audio on the Voted Audio Bus on the next polling loop.