Belar FMHD-1, Operator'S Manual

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FMHD-1 Operator’s Manual
Page 14 FMHD-1
3.5, 4.0, 4.5,
or
5.0
seconds. An “
Infinite
” hold-time is also possible. These are all set from
the Unit Settings Popup Menu.
In "
Past
” time mode (with “
Infinite: OFF
”), the FMHD-1 samples the appropriate signal stream
for the time interval set by the “
Hold Time
” parameter. The Peak indication is the highest reading taken
during that interval. The Average indication is computed from the peak values collected during that same
hold-time; the Minimum is the lowest modulation peak occurring during the hold-time.
In “
Real
” time mode (“
Infinite: OFF
”), the modulation or level stream itself controls the starting
points of the measurement time windows. In “
Rea
l” time, no matter the
Hold Time
setting, the
occurrence of a peak which exceeds the peak presently displayed causes the new, higher peak to be
immediately displayed. At the same moment, the Average modulation occurring since the previous update
is computed and displayed, along with the Minimum peak value for the interval. The window timer is
reset to zero, and the accumulation of modulation data is restarted. It continues until either an even higher
Peak reading occurs, or until the time passing since this most recent reset reaches the window length set
by the
Hold Time
parameter.
When the time parameter “
Infinite
” is “
ON
,” the highest Peak and Average readings are collected and
held until they are replaced by successively higher ones. Correspondingly, Minimum readings are
collected until replaced by successively lower ones.
4.4 FMHD-1 Bargraph Displays
Two of the FMHD-1 display screens have three-color bar graphs to indicate dynamically changing signal
levels. These tri-color bar graphs provide simultaneous indications of the Peak modulation or program
level (in red), the Average level (in yellow) and the Minimum level (in green). Characteristics of the
indications are controlled by settings in the Unit Settings Pop-up Menu. (See Section 6.3.1 on page 25.)
For all settings, the Peak indication is read at the right edge of the red portion of the bar. Likewise, the
right edge of the yellow portion of the bar indicates the Average value, and the right edge of the green
portion of the bars indicates the Minimum value occurring during the metering time window. (The space
between the three indications is filled for ease in reading.)
The preceding section, “ FMHD-1 Modulation/Program-Level Readings”, explains how the data for the
bargraph readings is obtained.
Descriptions of the two bargraph screens follow below under Section 5, “The FMHD-1 Display Screens”.
4.5 Spectrum Display
The user interface for, and the operation of the FMHD-1 spectrum display are presented in Section 7,
“ FMHD-1 Frequency Spectrum Display and Functions”, beginning on page 29.
5
The FMHD-1 Display Screens
5.1 Main Tuning Screen
The FMHD-1 Main Tuning Screen is an observation point for routine monitoring of FM IBOC
broadcasts. At the top center of the display is the carrier frequency to which the FMHD-1 is tuned. The