System for controlling a transfer function of a hearing aid

A system for controlling gain function of a hearing aid, the system comprising:

• a microphone adapted to convert a sound pressure to an input signal,
• a speaker adapted to convert an output signal to a processed sound pressure,
• a signal processor interconnecting said microphone and said speaker and adapted to process said input signal to said output signal according to a control signal, and
• a signal analyzer connecting to said microphone and to said signal processor, and
• wherein said signal analyzer -includes
• a first signal path having first detector adapted for maximum level and squelch level detection, where said first signal path includes a first filterbank adapted to separate said input signal into a first plurality of frequency band signals and where said first detector is configured to perform maximum level and squelch level detection for each of said first plurality of frequency band signals, and
• a second signal path having second detector adapted for compression level detection, where said second signal path include a second filterbank adapted to separate said input signal into a second plurality of frequency band signals and where said second detector is configured to perform signal level detection for each of said second plurality of frequency band signals, and
• a controller adapted to generate said control signal to control gain levels of said signal processor based on said first and second detector responses to said input signal such that a detection in excess of a maximum level threshold and /or below a squelching threshold in a frequency band signal in the first signal path causes a corresponding gain reduction in said signal processor and such that a detection of a signal level below a user's minimum detectable sound pressure in a frequency band signal in the second signal path causes a corresponding gain increase in said signal processor.