Temperature Related Information - Keysight N9912A Service Manual

Theory of Operation RF Analyzer

Temperature Related Information

N9912A
Temperature Related Information
Five temperature sensors are in the analyzer: two on the A4 RF board, two on the A5 system board, and one
in the battery pack.
• RF1—NA Temp Sensor (on the A4 RF board near the NA circuitry)
• RF2—SA Temp Sensor (on the A4 RF board near the SA circuitry)
• SB1—on the A5 system board near the headphone jack
• SB2—on the A5 system board near the battery compartment
• Battery pack—inside the battery pack
The battery pack has its own internal temperature sensor. The battery pack will shut itself down in the case
of extreme temperatures.
See Chapter 8 for instructions on viewing temperature readings.
See the FieldFox User's Guide, "FieldFox High-Temperature Protection" section, for information about
operation at high temperature.
The temperature readings for sensor RF2 are stored as part of the adjustment data for the Frequency
Response Preamp On/Off adjustments.
During normal operation, as each SA measurement is taken, the current RF2 temperature reading is
compared tot he temperature stored for the Frequency Response adjustment. A delta temperature is
calculated. Each SA measurement is adjusted to compensated for the delta temperature.
The internal temperature of the unit is critical when executing the TME based software for tests and
adjustments. See the TME help for detailed information.
Under typical bench top (indoor) conditions, the internal temperature of the unit will be about 20 ×C above
ambient once the internal temperature has stabilized. It will typically take 60 to 90 minutes for the internal
temperature to stabilize when a "cold" unit is turned on.
5-24 Service Guide N9912-90003