HP 3585A Service Manual page 40

Operation Overview
( + 1 5Vdc, - 1 2 . 6Vdc, 1 5 0mA max . )
1. The Terminated input is dc coupled. Peak (combined ac/dc in­
put) levels exceeding ± 13 volts will "trip " the internal protection
circuit causing the input to open, but such levels may also damage
the input circuitry.
2. RP input levels exceeding ± 5. 25 volts peak may damage the
High-Impedance input circuitry. The combined ac/dc input level
applied to the High-Impedance input must not exceed ± 42 volts
peak.
Activate Terminated input and select 500 or 750 dc-coupled termination .
Also used to select 500 or 750 calibration impedance for dBm measurements
at the High-Impedance input .
Lights indicate that Terminated input is terminated in 500 or 750, and also
indicate the calibration impedance .
Activates High-Impedance input ; deactivates Terminated input .
m
AUTO
Sets RANGE automatically as a function of the composite ac input-signal
level .
ENTRY Deactivates
keys .
GJ
o
OVERLOAD
Lights when ac input-signal level exceeds RANGE setting .
Couples Reference Level (amplitude of top graticule line) to RANGE . In­
REf L VL
TRACK
itially sets Reference Level equal to RANGE to maintain on-screen display.
OFF-�
The Reference Level can be set equal to RANGE at any time by turn­
ing
· See Operating Manual (Chapter 4) for additional information .
3 -8
I N PUT F U NCTl O N S *
-- -- -- --.
Probe Power J a c k
( 1
; prefaces RANGE , enabling it to be changed with STEP
GJ
off and then back on.
"��A� L
m [
RANGE
m re, gJ
,--
H igh-I mpedance I n put <
MO
3 0 pF, a c coupled)
Model 3 585A
0
OVERLOAD
REF LVL
AUTO
ENTRY
TRACK
0
OFF-ON
50n 7511
I Mll
MAX
Pk
1 3 V
42V
Terminated I n put
( 5 00 or 7 50 , d c coupled)