Instruction manual

ACU-1000 Operations Manual
2-32 Interoperability Now
Set TX Level
The proper TX level is required to fully modulate the transmitter, but not over modulate it.
Most radios have an audio limiter prior to the transmitter to prevent over modulation. Even
with the limiter, some radios will still over modulate and some even shut off the TX signal
when the input is too high. When the level is set too low the audio of the radio receiving the
signal will be lower than normal, requiring that its volume control be turned up to an abnormal
position. When the audio is too hot the audio will sound squashed or forced, and if the radio
does not have a TX audio limiter the audio will sound distorted and over modulated.
• Cross-connect the HSP Module to the DSP Module being adjusted, and use the HSP
Handset to key the radio while speaking at a normal volume level.
• Monitor to the TX audio of the interfaced radio on a receiver set to the radio’s TX
frequency.
• The quickest way to set the TX audio level is to use the ACU Controller to set the DSP
Module’s TX level to its lowest setting. Increase the TX level until the audio in the
monitoring radio stops increasing in level. This is the threshold point where the limiter
is preventing the TX level from going any higher. Leave the DSP Module’s TX level at
this threshold value.
• You may also follow the radio’s recommended TX input audio setting procedure.
• Click Apply to save the TX Level setting.
QB2 Is Equalization Required?
High Frequency Equalization either boosts or rolls off the high end of the RX audio spectrum.
This adjustment compensates for poor RX audio quality. The best way to determine the proper
High Frequency Equalization Setting is to listen to the received audio in the HSP handset (not
the HSP speaker, unless a high-quality external speaker is connected).
(QB2 Yes) Adjust Equalization
• Monitor the RX Audio in the HSP handset.
• If the audio sounds like it is lacking treble, the high frequencies can be increased
(boost).
• If the signal sounds too bright or harsh, the high frequencies can be attenuated (cut).
• When the best-sounding audio is attained, click Apply to save the setting.
Note: Most Motorola mobiles and portables sound best with a boost of at
least 3.5 dB.
(QB2 No) Flow Chart B Complete - Jump to QA3