H Heuer Instruments UMDT51A, Руководство пользователя

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Adjustment procedures
LT51 User Manual 78
TX Level
To adjust the transmitter output level of the LT51 press the [f1] Tx Level key.
Press the [f1] softkey until 600

is displayed for the ZRTX and ZTX impedances.
Terminate the LT51 TXa-b terminals with an external 600

load. Using a short,
low capacitance cable connect the TXa-b terminals to the high impedance input
of a DMM configured to measure ACV and display the measurement in dBm
referenced to 600

.
Use the knob on the LT51 to adjust the level displayed on the DMM to 0.00 dBm
and then press the key.
NOTE: The knob must be turned (even if the default TxLevel is correct ) to zero
the calibration constant, before pressing the key to save the new
value. If the knob is turned without saving the value, power cycle the
LT51 before continuing.
When the 600

Tx Level has been adjusted, press the [f1] softkey to adjust the
Tx Level for 75

and 50

. For each impedance follow the procedure outlined
above for the 600

adjustment, but with the appropriate termination. For these
two impedances, the level ranges of the LT51 are not adjusted, since the values
obtained during the 600

adjustment are sufficient.