HP 83751A User Manual page 248

Specifications and Options
Modulation
Rates:
50
Maximum deviation: same as unlocked mode up to 25 times the rate
Maximum deviation:
DC to 100 Hz rates: f75 MHz
100 Hz to 1 MHz rates: f 7 MHz
1 MHz to 2 MHz rates: f5 MHz
2 MHz to 10 MHz rates: f 1 MHz
Sensitivity:
-6 or -20
FM sensitivity with millimeter
Input impedance: 1 kohm
1 7 - 1 4
MHz/V
(See Chapter
head use.)
15, "Special finctions, "for