MODULATION
AMPLITUDE MODULATION
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:
10 dB/volt
Linear AM:
100% per volt
AM Depth (typical with RF level at 6 dB below maximum
rated output):
0-90% linear; 20 dB log
AM Bandwidth (3 dB, 50% depth):
DC to 50 kHz minimum
DC to 100 kHz typical
Maximum Input:
±
5V
FREQUENCY MODULATION
External FM Input: Front or rear panel BNC, 50
Ω
or 600
Ω
input impedance. All options selectable from modulation
menu. Carrier frequency is not phase-locked in FM mode to
facilitate wideband deviation.
FM Sensitivity: – 6 MH z /v o l t, + 10 MH z/v ol t, or
+20 MHz/volt, selectable from modulation menu.
Deviation:
Narrow Mode:
0 to 50 MHz peak minimum, DC to
500 kHz rates.
Wide Mode:
0 to 100 MHz peak minimum, DC to
100 Hz rates.
Distortion at 1 kHz: <10% typical
Maximum Input:
±
5V
SQUARE WAVE MODULATION
The RF output can be pulse modulated via an external modu-
lating signal or an internal square wave generator.
On/Off Ratio:
>50 dB
Rise/Fall Time: <1
µ
s typical
Internal Square Wave Generator: Four square wave sig-
nals (400 Hz, 1 kHz, 7.8125 kHz, and 27.8 kHz), selectable
from modulation menu.
Accuracy:
Same as internal or external 10 MHz time
base.
Square Wave Symmetry:
50%
±
5% at all power levels
External Input: Front or rear-panel BNC, selectable from
modulation menu.
Drive Level:
TTL compatible input
Minimum Pulse Width:
>5
µ
s.
Input Logic:
Positive-true or negative-true, selectable
from modulation menu.
REMOTE OPERATION
All instrument functions, settings, and operating modes (ex-
cept for power on/standby) are controllable using commands
sent from an external computer via the GPIB (IEEE-488
interface bus).
GPIB Address: Selectable from a system menu
IEEE-488 Interface Function Subset:
Source Handshake:
SH1
Acceptor Handshake:
AH1
Talker:
T6
Listener:
L4
Service Request:
SR1
Remote/Local:
RL1
Parallel Poll:
PP1
Device Clear:
DC1
Device Trigger:
DT1
Controller Capability:
C0, 1, 2, 3, 28
GPIB Status Annunciators: When the instrument is oper-
ating in Remote, the GPIB status annunciators (listed below)
will appear in a window on the front panel LCD.
REMOTE:
Operating on the GPIB (all instrument front
panel keys except for the SYSTEM key and the RETURN
TO LOCAL soft-key will be ignored).
LLO (LOCAL LOCKOUT):
Disables the RETURN TO
LOCAL soft-key. Instrument can be placed in local mode
only via GPIB.
Emulations: The instrument responds to the published
GPIB commands and responses of the WILTRON Models
6600 and 6700 signal sources. When emulating another sig-
nal source, the instrument will be limited to the capabilities,
mnemonics, and parameter resolutions of the emulated in-
strument.
PERFORMANCE
SPECIFICATIONS
681XXB OM
B-5