— 13 —
dio loss alarm delay
time, which is the num-
ber of seconds between
the onset of ‘dead air’
and a flashing LCD and
rear-panel alarm. The
delay may be programmed in one-second increments up to
2 minutes. To deactivate the alarm altogether, turn the
knob completely counterclockwise to
Audio Loss: OFF
.
Once the delay is set, push the knob again and
Threshold
will begin to blink. This is the programmable audio level
trip point at which the alarm function will recognize ‘dead
air.’ The trip point may be set for program peak levels be-
tween –30dB and 0dB. Do consider the dynamics of the
broadcast format when setting this delay. Even peaks in
Classical music will regularly exceed –20dB, and a setting of
60 seconds would probably accommodate most all
pianis-
simo
passages. A pop-music P.D. might ask for a setting of
1 second and 0dB, but use your own good judgment.
The rear-panel
A
terminal gives an NPN transistor saturation
to ground for an audio-loss alarm. The polarity (logic state)
of the alarm is set on one of the hidden menu screens that
are explained beginning on Page 20. This ground may be
used to actuate a relay, light an LED at a remote location or
tie-in with a remote control system.
FM Stereo Modes
(FM Menu Screen 7)
Enter this menu screen to set the FM reception mode. The
default state is
StMode: Stereo
. With this setting, the re-
ceiver will attempt to decode any FM stereo transmission
regardless of signal quality. In the
Stereo
mode, the noise-
reducing stereo-to-mono ‘blend’ feature, common to most
modern FM receivers, is
not
engaged. The FM
mode display in Menu
Screen 1 will show
FM:S
for stereo broadcasts
and
FM:M
if the station is
transmitting a monaural
signal.
The graphic on the second line of FM Menu Screen 7 repre-
sents the ‘wide’ soundstage that characterizes a normal ste-
— 14 —
reo transmission. When the stereo pilot is lost, the display
will collapse to the center.
Stereo-FM suffers a theoretical noise disadvantage of about
20dB when compared with monaural broadcasts. Push the
knob and turn it to select
Blend-St
.
This mode will mitigate
the noise situation sub-
stantially by progressive-
ly ‘blending’ the stereo
image to mono as the FM
signal deteriorates under
low-signal, multipath or other reception handicaps. This
mode is identified with
FM:B
in Menu Screen 1. The degree
of blending is not indicated on Menu Screen 1, nor will the
screen indicate
FM:M
if the transmission reverts to full
monaural when
Blend-St
is selected.
The bargraph on the second line in this menu does, in fact,
depict a ‘dynamic soundstage.’ As the circuit blends be-
tween full stereo and full mono, the actual blending action
will be indicated by a proportional narrowing of the
bargraph.
F-Mono
(Forced-Mono),
will force the INOmini
639 into a fulltime mon-
aural reception mode.
This might be desirable
when monitoring or re-
laying a station that never broadcasts in stereo.
Feel free to switch among the three options here. You can
evaluate the audible differences, either a noise tradeoff be-
tween
Blend-St
and
Stereo
, or a separation tradeoff be-
tween
Blend-St
and
F-Mono
. This blending option is in-
cluded in the INOmini 639 to at least offer a feature com-
mon to consumer radios, although it well may be consid-
ered ‘cheating’ in the professional workplace.
Program Audio Levels
(HD Radio Menu Screen 7; FM Menu 8)
This is a very accurate, peak-responding display of program
audio levels and includes a floating peak-hold function.
