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Problem:
Air Traffic Controllers have identified two significant problems with many current voice switches: |
High frequency tones accidentally induced into
their headsets, and
Improper balancing of the volume of incoming
calls (i.e. no Automatic Gain Control - AGC)
The consequences of these problems are significant:
The improper balancing of the volume causes
controllers to constantly re-adjust 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
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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| Solution
Digital Signal Products (DSP), Inc. has developed an Audio Signal Processor (ASP) that simultaneously solves both of these problems. The ASP uses a digital signal processor to perform Analog to Digital conversion of all incoming signals. |
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| 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. The ASP is placed directly behind the controller's head set jack box or it can be incorporated into a head set jack box.
The Tone Notching and AGC ASP has been successfully tested at the Oklahoma City FAA facility and at the Dallas/Ft. Worth (DFW) airport. After extensive testing this ASP unit has been successfully installed and operational at a number of FAA sites.
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