EndRun Meridian II, Руководство пользователя

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M e r i d i a n I I U s e r M a n u a l 114
C H A P T E R T E N
115 M e r i d i a n I I U s e r M a n u a l
R E A R - P A N E L I / O
Digital Output Module
The Digital Output Module is a “plug-and-play” option that adds four buffered outputs to your
Meridian II. Signal levels are either TTL (BNC connectors), RS-422 (DB9M) or RS-232 (DB9M).
Various output types are Programmable Pulse Output (PPO), Digital Time Code, Direct Digital Syn-
thesizer (DDS), 1 PPS and 10 MPPS. Output types are described below. See Appendix K - Specifi-
cations, Optional Digital Output Module for signal details. Below is an example of a Digital Output
Module.
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Digital Output Module - Programmable Pulse Output (PPO)
The Programmable Pulse Output (PPO) adds four independently programmable “on-time” pulses at
decade rates from 1 PPS to 10 MPPS (i.e. 1, 10, 100, 1k, 10k, 100k, 1M, 10M PPS). Other selections
are 1PP60S (pulse per 60 seconds, on the minute), 1PP2S (pulse per 2 seconds on the even second)
and Inverted 1 PPS (falling edge on time - not available in 2U chassis.) All these outputs are aligned
with the system time and with the other TTL outputs in the unit (except the DDS output, if any).
This format can be changed via the front-panel display by navigating to Main Menu > Option I/O >
OptCard > (see Chapter 12 - Front-Panel Keypad/Display ). Or, you can program the outputs via
the network or serial port by using console command
pluginoptsconfig
(see Chapter 3 - Console
Port Control & Status ).
Digital Output Module - Time Code
The format of all four outputs of the Digital Time Code will be the same format as that on the
standard CPU Module AM Code connector. This format can be changed via the front-panel display
by navigating to Main Menu > Option I/O > Sys I/O > TCodeOut (see Chapter 12 - Front-Panel
Keypad/Display ). Or, you can change the time code format via the network or serial port by using
console command
cpuoptsconfig
(see Chapter 3 - Console Port Control & Status ). When you
change the time code format selection, it affects ALL time code outputs in Meridian II.
Digital Output Module - Direct Digital Synthesizer (DDS)
Programmable synthesized pulse rates from 1 PPS to 10 MPPS in 1 PPS steps are available, includ-
ing 1.544 MPPS or 2.048 MPPS. The rate output is phase locked to the system oscillator. However,
it is not aligned with system time. The synthesized rate frequency can be changed via the front-panel
display by navigating to Main Menu > Option I/O > Sys I/O > DDS (see Chapter 12 - Front-Panel
Keypad/Display ). Or, you can change the synthesized rate via the network or serial port by using
console command
pluginoptsconfig
(see Chapter 3 - Console Port Control & Status ). When
DIGITAL OUTPUT MODULE (WITH PPO)