HP 8112A Operating, Programming And Servicing Manual page 204

1 0.3-4 Servicing the Timing and
Slope Generators
In TIME mode the ranges are from 1 0 ns to 99.9 ms and 50 ns to
500ns. In RATE mode, ranges are from 1 00 MHz to 1 0 MHz and
20 MHz to 2 MHz. Ranges are selectable as shown in Table 1 0.3-3.
Table 1 0.3-3. Timing IC Time/frequency Range Selection
Number c B A
Range Range
0 0 0 0 10
1 0 0 1 1
0 1 0 100
2
0 1 1 10
3
4 1 0 0 1
1 0 1 100
5
1 1 0 10
6
1 1 1 1
7
Analog control within each range is controlled by the FRQ IN (Pin 4)
current , derived from the appropriate DAC on the control board A2,
and the TIME IN ( Pin 5) current, derived from the control input via
the control mode switch U 130. The signal passes through a divider
circuits before being applied to the VCO .
RATE Mode
In the RATE mode, the timing IC output is a 50% duty cycle square
wave whose repetition rate is directly related to the internal range
data and the IFRQ input current
TIME Mode
In the TIME mode, the output signal repetition is identical to
the input trigger frequency but the output pulse width or delay,
depending on trigger mode selection, is directly related to the
internal store range data and the FRQ IN current from the relavent
DAC .
Selection of the above modes is made by using the MODE IN and
RATE inputs as shown below.
Table 10.3-4. Timing IC mode selection
TIME MODE IN MODE/OUTPUT
0
0
1
1
in
FREQ OUT Out WID or DEL
in
RATE Mode TIME Mode
- 100 10 ns - 100 ns
MHz MHz
100 ns - 1 µs
- 10
MHz MHz
1 µs - 10 µs
- 10
kHz MHz
100 10 µs - 100 µs
kHz kHz
-
-10 100 µs
kHz kHz
- 1 l ms - lO ms
Hz kHz
- 100 10
Hz Hz ms
- 10 100 ms - 1 s
Hz Hz
0
RATE RATE
1
used
Not
0
TIME TIME
1 used
Not
lms
-
- 100 ms