40
Programming
T801-4 Installation and Operation Manual
© Tait Electronics Limited September 2007
crossing within 40 seconds. The main purpose of this facility is to
synchronize CTCSS transmissions within a synchronous broadcast system.
It also has the effect of synchronizing the output frequency with the output
frequencies of other T801-4 units which have the same frequency setting.
This facility is available for frequencies
≤
260Hz and applies to all channels.
Attempting to set
Locked
and a frequency greater than 260Hz will raise a
warning.
CTCSS Phase
Reversal
Selecting the
CTCSS Phase Reversal
check box causes the output
frequency phase to be inverted on each toggle of the “Reversal Trigger”
input – this is a hardware input on the
I/O PORT
on the rear panel. Its main
use is in a PMR (simulcast) system which may require the CTCSS to be
reversed/inverted as the transmitter key is switched off. The intention is to
assist CTCSS controlled mobile receivers to close rapidly.
Control Voltage
The
DAC output
field shows the state of the master oscillator control
value, and is provided for information purposes only. However, selecting
the
Manual Adjust
check box allows you to set the value manually. In the
manual state the value will remain fixed.
Fault Outputs Delay
Entering a number of seconds into this field will cause the GPS status and
master oscillator alarms and front panel LEDs to be delayed by this amount
before activating. The purpose here is to mask alarms which are of short
duration. The maximum setting is 3600 seconds. If the ET
Status
LEDs
are flashing, an alarm has activated and is still within this delay period. The
factory default setting is 60 seconds. Refer also to
“Fault Output Delay” on
page 33
.
Timing Source
The
TTL Input
check box selects whether the 1PPS signal is supplied as a
TTL signal or as an RS-485 signal. This check box is
not
used
with the
T801-4. The TTL 1PPS input on
PORT A
is internally converted and
supplied to the Satsync 7 module as an RS-485 signal.
The
PPS Only
check box selects whether or not the Satsync 7 module will
validate the 1PPS signal using NMEA data (GPS fix):
■
When this check box is selected, the Satsync 7 module will ignore
NMEA data and assume the 1PPS signal is valid whenever it is present.
■
When the check box is clear, the Satsync 7 module will validate the
1PPS signal using NMEA data.
Leave both check boxes clear when:
■
The 1PPS source is either the Trimble internal GPS receiver (when
fitted), or the Dalman external GPS receiver.
■
You are using any other external 1PPS source and NMEA data is
provided.
