Instruction Manual - Amron International Inc.

INSTALLATION & OPERATIONOPTIONS (Continued) 6.11HELIUM SPEECH UNSCRAMBLER OPTION /26DSP2The Helium Unscrambler option is installed into the option panel located on right side of thecommunicator. A Communicator with this option accommodates a wide range of operating depths.This state of the art digital design can accommodate a multitude of functions ranging from thecorrection of the diver’s raw helium speech to normal intelligible voice levels, advance treble boostand complex noise reduction filters (NRF).Diver radios configured with this option are only supplied with the AC power option. This is due tothe power requirements of the Unscrambler option. The radio can be operated in the air mode byturning off the helium Unscrambler.The Unscrambler offers two modes of operation, Modes A and B. Mode A is typically used forshallow depths with lower concentrations of Helium, while Mode B is used for deeper depthsrequiring higher concentrations of Helium. Based on the mode setting, the frequency shiftingalgorithm’s function will automatically change as well.Amron’s advanced Noise Reduction Filter (NRF) incorporates a complex DSP algorithm whichfilters out background noise while allowing the diver’s speech to be clear and intelligible. AmronNRF automatically captures the frequency spectrum of applied background noise within the audiofrequency bandwidth and reduces it without affecting the diver’s speech. The NRF has fouradjustment levels for the reduction of background noise in both depth modes A & B. When inmode A, simply toggle the Mode Switch from A to B and back to A. In mode B, simply toggle theMode Switch from B to A and back to B. Each time a toggle cycle is completed, the filter willadvance to the next level. Based on the filter level, the operator will hear a number of beepingtones from 1-4 that corresponds with the blue LED indicators.The Treble Boost Control provides means of adjustment to enhance the diver’s microphoneperformance. The treble boost feature allows for optimum frequency enhancement and improvedintelligible speech from the diver’s voice.The Depth Control is used to change the amount of shift in the frequency of the diver’s voice. Thedepth control is advanced as the diver’s depth increases. There is a certain amount of interactionbetween the controls, and also a difference between diver voices, therefore it is necessary to tunethe unit to the diver. Intelligibility is the desired result; each operator will find a combination whichworks best. The frequency shifting algorithm changes the amount of correction to the raw heliumspeech.Simplex and Simulcom operations are possible with the Amcom Unscrambler. In Simplex mode,the tender's push-to-talk switch interrupts signals from the diver. In Simulcom mode, the tender willhear the diver at all times and tender must use a headset to talk to the divers without using thepush-to-talk switch. Use of a headset to monitor HeliOx speech is recommended to enhanceIntelligibility.23