HP 5300A - Page 30

'. Model 5300A
! Theory of Operation
Table 4-2. A1J1 Signals
SIGNAL NAME DESCRIPTION
Circuit operating voltages
Ground
Fl Signal to be accumulated in the counter after gating by the
control circuit.
"gn Goes low when the counter reaches 9% full scale.
F2 Input signal to the time base gated by the control circuit.
INHIBIT High during the measurement cycle, low during the display
cycle.
OPEN
Low
signal
forces
the
main
gate
flip-flop
to
the
open
position.
CLOSE Low signal forces the main gate flip-flop to the close
position.
LOG Logarithmic output pulse train from time base triggers main
i gate flip-flop on rising edge.
MGFF Main gate flip-flop signal is low when gate is open.
EXPONENT Inverted log pulses while main gate is open indicates number
of auto-ranging steps.
NO CONNECTION
RESET High signal resets all registers.
CLOCK 10 MHz reference signal from crystal oscillator
MAX TIME Low signal enables closing of the gate on next log pulse.
' Rising edge initiates display cycle.
TIME BASE OUTPUT Output from the time base decade position selected by the
time base select code on pins 22, 23, and 24.
PRINT Low signal provides print command to rear panel connector.
TRANSFER Low signal transfers data to display. High signal stores data.
1 MHz TIME BASE INPUT Input direct from plug-on bypasses control circuit.
TIME BASE SELECT A
Time base select code A, B, and C selects the time base
TIME BASE SELECTS division factor of the signal at the time base output at pin 18.
TIME BASE SELECT C
+22 V Full wave rectified voltage from the power transformer
secondary. Provides power to charge the battery pack. If
no battery pack is used, pin 25 is connected via the plug-on
to pin 50 (DC-IN).
Z| i
<
Pins 27 through 31 provide the drive to the annunciator
lights on the front panel. A low signal lights the corre-
sponding indicator.
Fi RIME|
MANUAL RESET Low signal from front panel pushbutton switch on rear panel
input clears the system to zero.
Low signal activates decimal point 1.
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