OTHER OUTPUT POWER SPECIFICATIONS
Output Power Resolution: 0.01 dB
Source Impedance: 50
Ω
nomimal
Source SWR (Internal Leveling):
Without Attenuator:
<1.7 at <2 GHz typical
<1.6 at 2 to 20 GHz typical
<2.0 at >20 GHz typical
With Attenuator:
<2.0 typical
Power Level Stability with Temperature:
0.04 dB/°C typical
Level Offset: Offsets the displayed power level to establish
a new reference level.
OUTPUT ON/OFF: Toggles the RF output between an Off
and On state. During the Off state, the RF oscillator is turned
off. The On or Off state is indicated by two LEDs located
below the OUTPUT ON/OFF key on the front panel.
RF On/Off Between Frequency Steps: System menu se-
lection of RF On or RF Off during frequency switching in CW
or Step Sweep modes.
RF On/Off During Retrace: System menu selection of RF
On or RF Off during retrace.
Internal Leveling: Power is leveled at the output connector
in all modes.
External Leveling:
External Detector:
Levels output power at a remote de-
tector location. Accepts a positive or negative 0.5 mV to
500 mV input signal from the remote detector. EXT ALC
ADJ adjusts the input signal range to an optimum value.
BNC connector, front and rear panel.
External Power Meter:
Levels output power at a re-
mote power meter location. Accepts a
±
1V full scale input
signal from the remote power meter. EXT ALC ADJ ad-
justs the input signal range to an optimum value. BNC
connector, front and rear panel.
External Leveling Bandwidth:
30 kHz typical in Detector mode.
0.7 Hz typical in Power Meter mode.
User Level Flatness Correction:
Number of points: 2 to 801 points per table
Number of tables: 5 available
Entry modes: GPIB power meter or computed data
CW POWER SWEEP
Range: Sweeps between any two power levels at a single
CW frequency.
Resolution: 0.01 dB/step
Accuracy: Same as CW power accuracy.
Step Size: User-controlled, 0.01 dB to the full power range
of the instrument.
Step Dwell Time: Variable from 1 ms to 99 seconds. If the
sweep crosses a step attenuator setting, there will be a
sweep dwell of approximately 20 ms to allow setting of the
step attenuator.
SWEEP FREQUENCY/STEP POWER
A power level step occurs after each frequency sweep.
Power level remains constant for the length of time required
to complete each sweep.
MODULATION
AMPLITUDE MODULATION
All amplitude modulation specifications apply at 50% depth,
1 kHz rate, with RF level set 6 dB below maximum specified
leveled output power, unless otherwise noted.
External AM Input: Log AM or Linear AM input, front or
rear-panel BNC, 50
Ω
or 600
Ω
input impedance. All options
selectable from modulation menu.
AM Sensitivity:
Log AM:
Continuously variable from 0 dB/volt to
25 dB/volt
Linear AM:
Continuously variable from 0% per volt to
100% per volt
AM Depth (typical): 0-90% linear; 20 dB log
AM Bandwidth (3 dB):
DC to 50 kHz minimum
DC to 100 kHz typical
Flatness (DC to 10 kHz rates):
±
0.3 dB
Accuracy:
±
5%
Distortion: <5% typical
Incidential Phase Modulation
(30% depth, 10 kHz rate): <0.2 radians
Maximum Input:
±
1V
FREQUENCY MODULATION
External FM Input: Front or rear panel BNC, 50
Ω
or 600
Ω
input impedance. All options selectable from modulation
menu.
FM Sensitivity: Continuously variable from
±
1 kHz per volt
to
±
20 MHz per volt (Locked or Unlocked Narrow FM modes)
or
±
100 kHz per volt to
±
100 MHz per volt (Unlocked Wide
FM mode), selectable from modulation menu.
(For 681X5B units, maximum sensitivity is divided by 2 from
1.0 to 2.2 GHz and divided by 4 from 0.5 to 1.0 GHz.)
FM Deviation:
681XXB OM
B-5
Changed: November 1995
Frequency
Range
(GHz)
FM Mode
Locked
(1 kHz to
500 kHz rates)
Unlocked
Narrow (DC to
500 kHz rates)
Unlocked
Wide (DC to
100 Hz rates)
0.5 to
≤
1.0
(681X5B)
The lesser of
±
2.5 MHz or
Fmod x 75
±
2.5 MHz
±
25 MHz
>1.0 to
≤
2.2
(681X5B)
The lesser of
±
5 MHz or
Fmod x 150
±
5 MHz
±
50 MHz
0.01 (>2.2 for
681X5B) to 65
The lesser of
±
10 MHz or
Fmod x 300
±
10 MHz
±
100 MHz
PERFORMANCE
SPECIFICATIONS
