HP 654A Operating And Service Manual page 12

Section III Model 654A
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FREQUENCY dial (Cl A/B/C): Varies test
frequency continuously within each frequency
range. Dial reading multiplied by range setting
gives the out put frequency in Hz of the 654A.
FREQUENCY RANGE switch (52): Selects one of
six frequency multipliers from Xl 0 to X 1M.
Output Meter (M I): Monitors amplitude of 654A
output prior to OUTPUT LEVEL attenuators.
Algebraic sum of meter indication and OUTPUT
LEVEL attenuator setting gives output power into
rated load.
Mechanical Zero Adjust: Allows meter to be
mechanically zeroed, when instrument is off.
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OUTPUT LEVEL (54): Attenuates 654A output
signal in nine steps of
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dBm each .
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OUTPUT LEVEL (54): Attenuates 654A output
signal in nine steps of 10 dBm each.
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UNBAL out put (14): BNC connector provides an
unbalanced output signal. at impedances of 50
ohms and 75 ohms.
BAL output (J3 and 14): BNC connectors provide
a balanced output signal at impedances of 135
ohms, 150 ohms and 600 ohms.
IMPEDANCE switch (A4S J): Selects required
output impedance of instrument; pushbuttons are
interlocked so that when one is pressed the others
spring out.
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AMPLITUDE control (R3): Allows adjustment of
+/-1 dBm of output signal amplitude.
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FREQUENCY VERNIER: Provides a fine
frequency adjustment for FREQUENCY dial.
@ LINE ON switch (51) and Pilot Lamp (DSI):
Switch applies primary power to instrument; pilot
lamp glows to indicate application of primary
power.
115 Vor 230 V Slide Switch (53): Sets instrument
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to operate from a primary power source of either
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15 V ac or 230 V ac, 48 Hz to 66 Hz.
FUSE (FI): 0.4 amp slow blow fuse protects
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instrument from overloads.
COUNTER OUTPUT (12): BNC connector
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provides signal output of greater than 0.1 V rms
into a 50 ohm load , at same frequency as front
panel out puts.
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Primary Power Connector (1 I): Connects primary
power to instrument.
Figure 3·1. Location of Controls, Indicators and Connectors
3·2