3-4
STRATA TX Operation Guide
400
Rev.
DC Superimposed Voltages
Powering the STRATA Transmitter
3.6
DC Superimposed Voltages
DC Voltage is applied to units directly or superimposed in the following way:
• DC Voltage is superimposed on the IF signal from the TCU to TXU.
• DC Voltage is superimposed on the RF signal from the TXU to HPU.
Note:
Currently, you can only power the HPU from the TXU.
How you power the STRATA transmitter depends on the particular application.
Be sure to read
"Powering STRATA Units," Section 3.4 on page 3-2.
Warning:
DC voltage superimposed with the
IF or RF signal may cause damage to test
equipment. Turn off DC voltage before
trouble shooting the transmitter.
3.6.1
DC Voltage Settings – Non Over-Ride Switch Models
Note:
If you are unsure which model transmitter you are using, see
"
Model Variations," Section 3.3 on page 3-1
.
Depending on how the transmitter is powered, the DC Voltage can be turned on
or off between the TCU and TXU, and between the TXU and HPU.
2.6.1.1
Turning DC superimposed Power On or OFF - TCU to TXU
To turn DC Voltages on or off between the TCU and TXU, do the following:
Step 1
Using the front panel control switch, turn the control switch counter
clockwise to the menu named “75 Ohm Coax.“The menu displays
either “Power On” or “Power Off” as shown in
Figure 3-7
:
Step 2
Press the control switch. The display will blink displaying the current
state.
Step 3
Press the control switch to select either “Power On” or “Power Off.”
Note:
If the transmitter is in transmit mode while changing the DC
power setting, the transmitter will automatically be placed in
standby mode. To place the transmitter in transmit mode, press
the control switch for one second.
2.6.2
Turning DC Superimposed Power On or OFF –
TXU to HPU
To turn DC Voltages on or off between the TXU and HPU, do the following:
Step 1
Using the front panel control switch, turn the control switch counter
clockwise to the menu named “NO HPU.” The menu displays either
“No HPU” or “HPU Present” as shown in
Figure 3-7
:Press the control
switch. The display will blink displaying the current state.
Step 2
Press the control switch to select either “No HPU” or “HPU Present.”
Note:
If the transmitter is in transmit mode while changing the DC
power setting, the transmitter will automatically be placed in
standby mode. To place the transmitter in transmit mode,
press the control switch for one second.
Figure 3-7 Setting DC Power from Front Panel Menus
TCU
POWER
SUPPLY
TXU
IF / DC
DC
RF / DC
HPU
Note:
TCU, TXU, and HPU
at the same location.
This method is recomended
for powering co-located
systems when power can
not be applied to TXU.
75 Ohm Coax
Power On
Power On
Power Off
Options:
HPU Coax
HPU Present
HPU Present
Options:
No HPU