Microphone assembly for speech recording using noise-adaptive output level control

A microphone assembly for recording speech characterized by a speech burst rate, with a noise-adaptive automatic output level control for an associated tape recorder having automatic gain control means, said microphone assembly comprising:

• transducing means for transducing an electrical audio signal with minimal distortion of directional characteristics;
• input amplifier means connected to said transducing means and including an output;
• means coupled to said transducing means and to said input amplifier means for attenuating the fundamental and first formant of said signal;
• automatic gain control means connected to the output of said input amplifier means;
• output amplifier means connected to the output of said input amplifier means and to said automatic gain control amplifier means and including controllable high-frequency bandwidth limitation means;
• and speech-noise differentiating means connected to said automatic gain control amplifier means and detecting presence of said speech burst rate with the fundamental and first formant attenuated to derive a control voltage representing percentage of speech, said control voltage being applied as control inputs to both the automatic gain control amplifier means and the bandwidth limitation means resulting in the generation of a constant level for processing by the automatic gain control means of said associated tape recorder.