B&K Precision 1823A - Manual - Manual (Page 11)

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the knob out and rotating it varies the level from
negative to positive around the mid point.
INPUT C, BNC : Input for frequency measurements above 80 MHz
Female BNC connector terminated in 50

.
LOW PASS FILTER : With this switch pushed in, the input B is routed
through a SWITCH(LPF) low-pass filter with -3 dB
point of approximately 100 kHz. When it is released,
the input B signal is applied to the counter. Same as
input B function for input A.
ATT. SWITCH : When this switch is set to x 10 (pushed in) the input
B is attenuated 10 :1 before application to the counter
with the switch set to x 1 (pushed out), the input B
signal is applied.
The attenuator has no effect on the input C.
INPUT B, BNC : Input for frequency measurements below 100 MHz
Female BNC connector terminated in 1 M

input
resistance, shunted by < 40 pF capacitance.
COUPLE. SWITCH : The switch is used to select the input-coupling mode
AC or DC.
COM/SEP. : COM. or SEPARATION for INPUT A,B
INPUT A, BNC : Input for frequency measurements below 100 MHz.
Female BNC connector terminated in 1 M

input
resistance, Shunted by < 40 pF capacitance.
GATE TIME SWITCH : This switch selects the degree of resolution of the
display in all modes except TOTAL.
HOLD SWITCH : In hold function the display held but the counters
continue to increment. When the hold is released, the
display is updated and resumes counting.
SLOPE SWITCH : Selects positive going or negative going edge of input
A, B signal for triggering. When pushed in, negative
going edge is selected; when pushed out, positive
going edge is selected.
FUNCTION SWITCH : Select the desired operating mode.
a. FREQ. A. When this mode is selected, the counter
reads the frequency of the input A.
Resolution is selected using the GATE TIME.
b. FREQ. B. When this mode is selected, the counter
reads the frequency of the input B. Resolution is
selected using the GATE TIME.
c. FREQ. C: When this mode is selected, the counter reads
the frequency of the input C. All readings are in MHz.
d. PERIOD A. When this mode is selected, the counter
read the period of the input A Resolution is selected
using the GATE TIME.