Instruction manual

ACU-1000 Operations Manual
2-90 Interoperability Now
2.17 Description of Configuration Items
2.17.1 HSP-2A Configuration Items
There are no configuration items for the HSP-2A module.
2.17.2 DSP-2 and Legacy Module DSP-1 and RDI-1 Configuration Items
2.17.2.1 Receive Audio Level (DSP and Legacy Module RDI-1)
This configuration item adjusts the audio receive level for a selected DSP-2 or RDI-1. A
correct receive level setting is required to ensure proper operation. Too high a level may cause
flat-topping and distortion, while too low a level won’t provide adequate audio volume. The
front panel SIGNAL LED is provided as a guide to setting the level; raise the receive volume
until the SIGNAL LED flashes momentarily on voice peaks. If the LED never lights, the level
is too low; if the LED is on nearly continuously, the level is set too high. The following
procedure is suggested:
• Connect the normal audio source to the module, and place the module in the program
mode.
• Set the module at its least-sensitive setting. If the SIGNAL LED is flashing on voice
peaks, this setting is correct. If the LED is now on continuously, the incoming audio
level is higher than can be accommodated by the DSP-2 or RDI-1 module, and must be
attenuated before reaching the module. If the SIGNAL LED is not flashing at this
lowest setting, the module’s gain must be increased; proceed to the next step.
• Raise the module’s receive gain one step at a time until the SIGNAL LED is flashing on
voice peaks (until the LED is flashing during voice peaks but is not lit continuously).
• Among the DSP-2 module’s algorithms is a Peak Limiter to prevent clipping of loud
audio peaks. This limiter has a fast attack time and slow recovery rate.
2.17.2.2 Transmit Audio Level (DSP-2 and RDI-1)
This configuration item allows a module’s transmit (output) audio level to be programmed. The
transmit level must be set correctly to insure proper operation of radios or other equipment
connected to this output. Too high a level may cause flat topping, distortion, or over-
modulation of a connected radio, while too low a level won’t provide adequate audio volume or
modulation level. If the actual audio level requirement of the radio or other connected
equipment is known, select this level from the Transmit Audio Level row of Table 2-18. These
levels assume a 600-ohm termination. If the required level is not known, the following
procedure is suggested:
• An input audio source for the module is required (so this audio can be sent back out
through the transmit audio port). Use the Connect command to create a connection
between the module to be programmed with second module (which is providing audio),
and then place the first module into the programming mode.