8662A Option H25
08862-92039
Page 2 of 17
3-56. The following procedure describes the setup and operation of the 8662A Option H25 in
the DFA mode.
CAUTION
Pins
1
through 15 and 19 on the DFA connector accommodate positive-true (1)
CMOS logic levels. Since these lines drive CMOS gates, they are static
sensitive. Connection and/or removal of plugs to the rear-panel DFA connector
should be performed with the 8662A turned off or unplugged.
1.
Turn the 8662A on. Set the desired modulation and output levels, and any
RF frequency in the range from 10 to 119.99 MHz. This may be done
manually or via HP-IB.
2.
Refer to Figure 2-4 and Tables 3-11 and 3-12 for descriptions of the parallel
format unitized with Option H25 as well as the logic levels required on each
pin of the DFA connector.
3.
Enable the DFA mode by applying a negative-true (1) TTL logic level to pin
18 (HOPEN) of the DFA connector.
4.
30 MHz is the DFA reference frequency from which other output
frequencies are determined. To program the 30 MHz reference frequency,
apply logical levels to inputs B0 through B16 (pins
1
through 17 of the DFA
connector).
5.
Data present at the DFA input is latched onto the frequency data lines
following a positive-going CMOS level transition at the DATSTRB input
(pin 19). To determine the next output frequency (following the next
positive transition on the DATSTRB line), total the frequency offsets of bits
3 to 16 that have true logic levels applied to them (from Table 3-11). Add
this total to 30.0 MHz. Then determine the frequency offset from bits 0 to 2
from Table 3-12 and add this total to the previous total.
Example: Only bits 2, 4, 5, 8, 11 and 13 have logic true (1) levels
applied. To determine the output frequency, add the frequency
offsets of bits 4, 5, 8, 11 and 13 to 30.0 MHz:
0.05 + 0.1 + 0.8 + 6.4 + 25.6 + 30.0 = 62.95 MHz
To this total, add the frequency offset for bit 2 true and bits 0
and
1
false:
62.95 MHz + (-0.005 MHz) = 62.945 MHz
Copyright 1986 - HEWLETT-PACKARD COMPANY - Spokane Division
24001 E. Mission Ave, Liberty Lake, WA 99019-9599 U.S.A.
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