681XXC OM A-3
AUX I/O: 25-pin connector that provides for single cable interface with another 68XXXB/C (master-slave
operation) and with other Anritsu instruments such as the Anritsu 56100A Scalar Network Analyzer.A
pinout diagram for this connector is shown in Figure A-2.
HORIZ OUT:Provides a 0V to 10V ramp during all sweep modes, regardless of sweep width. In the CW
mode, provides a voltage between 0V and 10V proportional to the full frequency range of the instrument.
When the CW Ramp is enabled, connector provides a repetitive 0V to 10V ramp. BNC connector, 50W
impedance.
10 MHz REF IN: Accepts an external 10 MHz ±100 Hz, 0 to 10 dBm time-base signal. Automatically
disconnects the internal high-stability, time-base option, if installed. BNC connector,50Wimpedance.
10 MHz REF OUT:Provides a 0.5 Vp-p, AC coupled, 10 MHz signal derived from the internal frequency
standard of the signal generator. BNC connector,50Wimpedance.
AM IN: Accepts an external modulating signal to produce AM on the RF output. AM sensitivity (linear or
log)and input impedance (50Wor 600W) are selectable via front panel menu or GPIB. BNC connector.
FM IN: Accepts an external modulating signal to produce FM on the RF output. FM sensitivity and input
impedance (50Wor 600W) are selectable via front panel menu or GPIB. BNC connector.
IN: Accepts an external TTL level signal to square wave (pulse) modulate the RF output. BNC
connector.
EXT ALC IN: Provides for leveling the RF output signal externally with either a remote detector or a
power meter.Connector accepts a positive or negative 0.5—500 mV signal from a remote detector or a
±1V signal from a remote power meter. BNC connector.
Line Fuse: Provides over-voltage/current protection for signal generator circuits during operation and
standby.Unit requires a 5A, type T fuse for 110 Vac line voltage or a 2.5A, type T fuse for 220 Vac line
voltage.
LINESELECT Switch: Provides selection of 110 or 220 Vac line voltages. When 110Vac is selected, the
681XXC accepts 90-132 Vac, 48-440 Hz line voltage; when 220 Vacis selected, the 681XXC accepts
180-264 Vac, 48-440 Hz line voltage.
InputLine Voltage Receptacle: Provides for connecting line voltage to the 681XXC signal generator.
IEEE-488 GPIB: 24-pin connector that provides for remotely controlling the signal generator from an
external controller via the IEEE-488 bus (GPIB). Apinout diagram for this connector is shown in Figure
A-3.
SERIAL I/O: Provides access to two RS-232 terminal ports to support service and calibration functions
and master-slave operations. RJ45 connector.
Figure A-1. Rear Panel, Series 681XXC Synthesized Signal Generator (2 of 2)
REAR PANELCONNECTORS
10
11
12
9
8
7
13
1
2
3
4
5
6