Belar FMHD-1, Operator'S Manual

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FMHD-1 Operator’s Manual
Page 22 FMHD-1
outputs. (These selections are made in the Output Settings Popup Menu, as described on page 26.) A
single red indicator in a column may indicate that the decoder assigned to that column is not present in the
unit, or that the audio program assigned to that row is not available in the broadcast, or both. In this
screen, red indicates a
non-functional condition.
Decoder
D1
is used to calculate the time and level alignments between the analog and digital portions of
a hybrid IBOC transmission. So D1 is typically assigned to the Main HD program
HD1
. Otherwise, these
indications in the Time Alignment Screen will indicate “
*** Out of Range ***
”.
Changes to the allocation of all the decoders present in the FMHD-1 to the available program streams
may be made in this screen. (Only inputs to HD Decoder D1 may be controlled from the Main Tuning
Screen.) Once the Program Selection Screen appears, momentarily depress the rotary encoder. This sets
the cursor at
D1 . Rotating the encoder will move the cursor through the four decoder choices and the exit
icon
▲
▼
▲
▼
in a wrap-around manner. Once the cursor is placed at the desired decoder, tapping the encoder
knob will highlight the marker green. Turning the encoder knob then will move the cursor down (or up)
through the eight rows of possible audio programs and the decoder at the top of the column, in a wrap-
around fashion. Once the cursor is placed in the desired program row, tapping the encoder will highlight
the enunciator green (if both the program and the decoder are available). If the enunciator lights red, the
assignment is non-functional.
To exit after setting a decoder input, move the cursor to the decoder marked at the top of the present
column and momentarily depress the encoder knob. The decoder designator will turn yellow. Advance
the cursor to the exit symbol
▲
▼
in the upper-right of the screen and again tap the encoder knob. Rotation
of the encoder will advance through the screens in the display.
5.8 BER Data Screen
This screen provides readouts of bit-error-rate information useful for evaluating transmission performance
of the hybrid FM IBOC system. For the BER testing, special data test sequences are generated in the HD
Exciter. These data sequences are decoded and analyzed by test algorithms running in the HD decoder in
the receiving
FMHD-1 .
When the BER test mode is activated at the HD Exciter, bit-error performance for the P1, P2, and P3
Primary logical channels, along with block-error performance for the PIDS (Primary IBOC Data
Services) logical channel is displayed. The number of bits (and blocks) processed, the number of errors
occurring, and the error rates are all displayed. During normal HD broadcasts, the twelve readouts
indicate “
N/A
”, for Not Available.
To run a test, the BER test sequences are activated at the HD Exciter. The FMHD-1 cursor is advanced
to “
Acquire
” in the BER screen by the rotary encoder, and the encoder momentarily depressed. The
FMHD-1 begins accumulating and displaying error data. Moving the cursor to “
Reset
” and depressing
the encoder knob restarts the counts. This allows determining whether adjustments in the transmitter
plant have affected the system performance without completely restarting the test procedure.
If the BER Test Mode is de-activated and subsequently re-activated at the HD Exciter, the
Acquire
command must be re-issued to initiate a new measurement sequence in the FMHD-1 decoder.