RDVS-D Tone Notching and AGC Print friendly page

Problems:

 Air Traffic Controllers have identified three significant problems with many current voice switches:
  • High frequency tones accidentally induced into their headsets
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  • Improper balancing of the volume of incoming calls (i.e. inadequate or no Automatic Gain Control - AGC)
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  • High Idle Channel Headset Noise even when no call is in progress. The consequences of these problems are significant:
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  • The improper balancing of the volume causes controllers to constantly re-adjust volume settings for ground-to-ground (G/G) and air-to-ground (A/G) calls and increases the probability that a critical message could be missed. This increases the controller's workload and induces a significant safety hazard
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  • The high frequency tones are a health issue since they cause extreme pain, temporary loss of hearing and, in some cases, permanent hearing damage. These can result in both short-term absences from work (one day to several weeks) and long-term disabilities
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  • High Idle Channel Headset Noise results in unnecessary controller fatigue and could become a safety issue during peak busy times
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    Solution

    Digital Signal Products (DSP), Inc. has developed an Audio Signal Processor (ASP) that simultaneously solves all of these problems. The ASP uses a digital signal processor to perform Analog to Digital conversion of all incoming signals. The digital signal processor analyzes the signal and removes up to two extraneous tones simultaneously within 70 milliseconds. This operation is performed without reducing the quality of normal voice signals.

    The ASP also measures the strength of all incoming voice signals and adjusts the volume of all calls to the same level. A controller can select one volume that is comfortable and all incoming voice calls are adjusted to this volume. For the 400D switch application, the ASP chassis is installed in the equipment rack and the position cable re-routed through it. Each card has 4 audio channels to accommodate headset and loudspeaker paths of a regular or a split position. To prevent any ground noise or hum interference all input output connections are done through transformers or opto-couplers.

    The Tone Notching and AGC ASP has been successfully tested at the Oklahoma City FAA facility. After extensive testing this ASP unit has been successfully installed and operational at a number of FAA sites, such as Dallas Ft. Worth, Chicago O'Hare, etc.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     


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