User’s Guide – 900MHz Stereo Audio Transmitter & Receiver
9
Setting the Transmitter’s Audio Modulation Level
With an active audio source connected to the transmitter’s
AUDIO
INPUTS
,
adjust the
AUDIO LEVEL
control on the front panel such
that the green
MODULATION LEVEL
OK
indicator is illuminated
whenever audio is present, and the red
PEAK
indicator flashes only
on the loudest audio transients. To prevent distorted audio at the
receiver, the red
PEAK
indicator should not be illuminated
continuously.
IMPORTANT!
Properly setting the transmitter’s modulation
level is CRITICAL to satisfactory operation of
the transmitter and receiver. If the level is set
too low, the receiver will likely be plagued with
objectionable background noise (hiss). If the
level is set too high, distorted audio and/or
interference on adjacent channels is likely to
result.
Note:
The audio source device may have a volume control that
adjusts the level of the audio signal(s) being fed to the transmitter’s
inputs. If your source device (e.g. MP3 player, portable CD player,
or PC sound card) is so equipped, initially set that device’s volume
control to its approximate midpoint. Then, adjust the transmitter’s
AUDIO LEVEL
control as described above. Use the following
guidelines to “fine tune” the settings:
•
If the audio output at the receiver suffers from excessive
background noise, the source device’s volume level is
probably set too low. Increase the source device’s volume
control a bit, and readjust the transmitter’s
AUDIO LEVEL
control accordingly.
•
If the audio output at the receiver is distorted, and/or if the
transmitted audio program can be heard on (or interferes
with) either or both of the channels adjacent to the selected
channel of operation, the source device’s volume level is
probably set too high. Reduce the source device’s volume
control a bit, and readjust the transmitter’s
AUDIO LEVEL
control accordingly.
10
Applied Wireless, Inc.
Mic Modulation Level Adjustment
With no audio on the audio line input, set the mic level adjust for
the appropriate LED indication on the Peak lamp as above. The
ALC switch may be either on or off, however it is recommended
that it normally be used in the ON position to prevent over-
modulation distortion.
Adjusting Headphone Volume (Receiver)
If desired, stereo headphones or earbuds equipped with a standard
3.5mm mini-phone plug may be used with the PAR900M. Insert
the plug into the
HEADPHONE
jack on the rear panel. The output
level at this jack may be adjusted using the
VOLUME
control on the
front panel.
Note:
The receiver’s
VOLUME
control only affects the volume at
the headphone jack. It does not affect the volume at the receiver’s
line level audio output phono jacks.
Internal Settings
The receiver has no internal user selectable settings or adjustments.
The transmitter has only an adjustment for the transmitter
headphone monitor output level (R30). Changing any other
internal setting will negatively affect the systems performance.
CAUTION!
The PAT900 transmitter and the PAR900M receiver both
contain sensitive electronic components on their
respective circuit boards. These devices can be
permanently damaged by static discharge if adequate
anti-static procedures are not observed. Such damage is
not covered by the Applied Wireless, Inc. Limited
Warranty. Before attempting to modify any of the internal
settings, discharge any static that may have accumulated
on your body by touching a metal object or surface that is
earth grounded, such as a cold water pipe. In addition,
your work area should be as static-free as possible (for
example, do not work in an area in which the floor is
covered by nylon carpeting).
