Boonton 8201 Modulation Analyzer Quick Start - Manual (Page 13)

13
SPCL 1-4 (MODULATION RANGE SETTINGS)
SPCL functions 1 through 4 permit the operator to select the modula-
tion display range. This is useful for speeding up measurements
where modulation may be removed temporarily, or in situations
where the modulation range is known. This feature is also useful
when decreased display resolution is desired. SPCL 1 is the default
function which is auto range. The others are:
SPCL2 5.000 full-scale
SPCL3 50.00 full-scale
SPCL4 500.0 full-scale
SPCL 5 (ENABLE SLOW PEAK DETECTOR MODE)
SPCL function 5 is provided to slow the response of the peak detec-
tors for modulation signal frequencies below 200 Hz. The detec-
tors are optimized for signal frequencies greater than 200 Hz for
maximum measurement speed. Below 200 Hz additional filtering is
required.
SPCL 6 (DISABLE SLOW DETECTOR MODE)
SPCL function 6 allows the operator to cancel SPCL 5. This is the
default setting.
SPCL 7 (SET PRE-DISPLAY DE-EMPHASIS)
SPCL function 7 allows the operator to change the de-emphasis
filter location from post -display to pre-display. This means that the
de-emphasis filters will affect the displayed modulation readings as
well as the AF OUT signal. This is useful for comparison of receiver de-
emphasis networks to the precision network used in the Model 8201.
SPCL 8 (SET POST-DISPLAY DE-EMPHASIS)
SPCL function 8 allows the operator to change the de-emphasis filter
location from pre-display to post -display. This means that the de-
emphasis filters will not affect the displayed modulation readings,
but will affect the AF OUT signal. This is the default setting for the
de-emphasis filters.
SPCL 11 and 12 are related to setting dB resolution for ratio mea-
surements.
SPCL 15, 16 and 17 are related to IEEE-488 which is described in
details on the Table 3-2 of the instruction manual.
SPCL 30 (MODULATION DETECTOR CALIBRATION):
SPCL function 30 is the modulation detector calibration program.
When executed the –CAL- message will appear in the FREQUENCY/
LEVEL display and detector calibration will begin. The calibration rou-
tine will take about 80 seconds to complete. The AM detector is cali-
brated first, followed by the rms detector, the FM detector and finally
the PM detector. If calibration error occurs, they will be displayed as
the particular is being calibrated.
Displayed Messages
UNLOC message
When the Model 8201 unlocks, the FREQUENCY/LEVEL display will be
overwritten with the ‘UNLOC’ message and the AUDIO and MODU-
LATION displays will be overwritten with the [= = ] symbol, which
means display out of range. When a valid carrier is acquired, the
displays will return to normal.
‘IFHI’ and ‘IFLO’ messages
The ‘IFHI’ and ‘IFLO’ messages appear in the modulation display and
indicate that the intermediate frequency level is not within range to
make an accurate measurement. SPCL functions 13 and 14 allow the
operation of these messages to be modified.
‘-CAL-’ Message
When the CAL key is depressed, or during the execution of SPCL
function 30, the message ‘-CAL-’ is written to the FREQUENCY/LEVEL
display to indicate that a calibration sequence is in progress.
‘Error’ message
A normal error response is for the word ‘Error’ to appear in the FRE-
QUENCY/LEVEL display followed by a number indicating the nature of
the error. Error codes are tabulated in Table 3-8 of the 8201 instruc-
tion manual along with a description of the error.
‘SELFCHK’ message
The message ‘SELFCHK’, followed by a changing digit, appears in the
FREQUENCY/LEVEL display at power on, and indicates that a hard-
ware check is in progress. Any error messages displayed indicate a
hardware problem. See Table 3-8 of the 8201 instruction manual for
the meaning of any reported errors.
Other displayed messages are described in detail in the pertinent
operation section.
Special Functions
Several of the Model 8201 operating features are internally pro-
grammable by selecting a SPCL function. These functions allow the
operator to change measurement configuration, as well as change
the hardware state of the instrument. Some of the more useful
SPCL functions are listed, the others are included in Table 3-2 of the
instruction manual.
SPCL 0 (CLEAR ALL SPECIALS)
SPCL function 0 allows the operator to reset any active SPCL func-
tions. The instrument special status is returned to the defaults
indicated in Table 3-2 of the instruction manual.