Specifications

NOTE
When loading a Result File for calculating Sigma vs. Tau,
the carrier frequency used for the measurement must be
entered in the Instrument Parameters display in order to
compute accurate values.
Detector/Discr. Input Frequency is the frequency of the input signal
connected to the HP 11848A's phase detector. The Detector/Discriminator
Input Frequency is used to:
• Select the appropriate Low Pass Filter (LPF) in the HP 11848A Phase
Noise Interface. For frequencies < 95 MHz, the system enables the
2 MHz LPF to eliminate feedthrough of the fundamental signal and
the additive products out of the phase detector. When the 2 MHz LPF
is enabled, the maximum offset frequency the system can measure is
2 MHz.
• Set the frequency of the Reference Source when the Reference Source
is under system control.
• When using an HP 11729C under System Control, the HP 3048A will
derive the correct Detector/Discr. Input Frequency and enter it into the
Instrument Parameter display. If the currently entered Detector/Discr.
Input Frequency is less than 95 MHz, and you are allowing the
HP 3048A to input the correct Detector/Discr. Input Frequency by
computing the value from a System Controlled HP 11729C, then the
measured offset range will be limited to 2 MHz. To eliminate this
problem, set the Detect/Discr. Input Frequency to a frequency greater
than 95 MHz.
Instr. Params: $N w/PLL 2-15