Doc. No. 1693-D03 Revision B 6/6/00
7
7 RECALL SETUP - In this mode, the user can recall one of the five user setups. Select the setup
number with the FREQ UP / CYCLE key and press the FREQ DOWN / ENTER to restore the
saved configuration.
8 SET D - This mode allows the user to select a sub-harmonic of the external reference input. The
external reference frequency will be divided by this value and used to synchronize the chopper
blade. The sub-harmonic can be used with the harmonic multiplier, N, to create fractional
harmonics (i.e. chopper frequency, f
chopper
= REF
EXT
* N / D).
Note: The Harmonic, N, and sub-harmonic, D are only available when using the external
reference input and a single frequency chopping blade (i.e. 10, 15, or 30 slot blade).
9 SET N - This mode allows the user to select a harmonic of the external reference input. The
external reference frequency will be multiplied by this value and used to synchronize the chopper
blade. The harmonic multiplier can be used with the sub-harmonic divider, D, to create fractional
harmonics (i.e. chopper frequency, f
chopper
= REF
EXT
* N / D).
10 REF SELECT - This key allows the REF OUT signal to be selected from a number of sources
depending on the operating mode selected.
Operating
Mode
Available sync sources
Internal Reference Mode: OUT, SYN
External
Reference:
OUT
2-Frequency Blade:
OUT, SYN, SUM, DIFF
Where: OUT = chopper wheel frequency (for the 2-frequency blade, the outer blade frequency)
SYN = the internal frequency synthesizer (or the harmonic generator for the external
mode)
SUM = sum frequency for the 2 frequency blade
DIFF = difference frequency for the 2 frequency blade
11 PHASE ADJ - a 12-turn pot to continuously adjust the chopper wheel phase from -
π
to +
π
.
12 REF OUT - the reference output signal selected by the REF SELECT mode (CMOS logic level).
13 EXT REF IN - the external reference signal is connected to this input BNC (TTL / CMOS logic
level).
14 EXT EN - Pressing this key toggles the MC1000 between the internal and external reference
mode. When the unit is in the external reference mode, the LED next to this key is lit.
