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Section IV – Operating Instructions
General
The TEGAM RF Power Standards are designed to be employed as the fourth arm of a bridge configuration.
These units are designed as the sensing element in RF power calibration and measurement systems.
These systems employ other electronic elements to effect control of the measurement routines. An
example of this type of system is the TEGAM PMX18-001 Power Sensor Calibration System. Proper use of
these standards and the TEGAM PMX18-001 is further documented in other TEGAM Operation and Service
Manuals. The Working RF Power Standard (Model 2505A) are feedthrough mount-splitter combinations are
used to calibrate thermoelectric, diode, and thermistor power sensors. The Reference RF Power Standards
(Model 1505A) are terminating thermistor mounts commonly used as a reference standard for calibrating
working standards.
Model 2505A Connector Descriptions
Figure 4.1 TEGAM 2505A Connectors
RF IN connector
SMA female connector connects to signal generator output. The RF power that comes in this connector is
applied equally to the DUT and the power standard. The fact that equal RF power is applied to both the
power standard and the DUT is what allows the determination the calibration factor of the DUT. There is at
least 6 dB and as much as 8.5 dB of insertion loss in the RF in path of the power splitter, plus the loss in
the standard.
BIAS VOLTAGE/Heater combination connector
A combined connection is used to connect the thermistor element to a DC Substitution bridge circuit and
the heater control circuit as is found in the TEGAM Model 1830A, 1806A, and 1806. The bridge operates
on the principal of DC substitution, so only DC voltages and currents are present at these terminals when
connected. In addition, the TEGAM Model 1805B can be used to heat the 2505A and 1505A with cable CA-
29-48.
SENSOR connector
Type N female coaxial connector provides the RF power to the DUT. The RF power applied to RF IN
connector is applied equally to the DUT and the internal thermistor mount. The fact that equal RF power is