Active audio compressing in telecommunication

Abstract

An output reducing system for a telephone system, e.g., implemented in a headset, includes an input line and an output line, wherein the input line transmits an incoming signal to an output transducer and the output line transmits an outgoing signal from an input transducer, and a compressor system is provided in the input line for reducing the output signal level.

1. An output reducing system for use at an end of a telephone system, the output reducing system comprising an input line and an output line, where the input line receives an incoming audio signal with an input signal level and transmits an incoming signal to a speaker and where the output line transmits an outgoing signal from an input transducer, and a compressor system in the input line for reducing an output signal level, wherein said compressor system comprises: an electronically adjustable shunt resistance mounted in parallel with the speaker and consisting of a MOS-FET transistor, a fall resistance in series with the speaker, said fall resistance being variable in response to the input signal level applied on the input line and is a positive temperature coefficient resistance, and a rectifier diode and a capacitor acting as a peak detector. 
     
     
       2. A system according to  claim 1 , wherein the compressor is adapted to be operable on the incoming audio signal alone, without additional power supply. 
     
     
       3. A headset including an output reducing system according to  claim 1 . 
     
     
       4. An output reducing system comprising an input line, where the input line is transmitting an incoming audio signal to an output transducer, where in connection with the input line a compressor system is provided for reducing the output signal level, and where the compressor system is adapted to be operable to be activated by power of the audio signal, without additional power supply. 
     
     
       5. A system according to  claim 4  wherein said compressor system comprises an electronically adjustable shunt resistance mounted in parallel with the output transducer. 
     
     
       6. A system according to  claim 5 , where the electronically adjustable shunt resistance is a MOS- FET transistor.   
     
     
       7. A system according to  claim 5 , wherein the compressor system further comprises a variable resistance. 
     
     
       8. A system according to  claim 7 , where the resistance is variable in response of the load implied on a headset that includes the output reducing system. 
     
     
       9. A system according to  claim 8 , where the resistance is a so- called PTC resistance.   
     
     
       10. A system according to  claim 5  wherein said compressor system further comprises a fall resistance in series with the output transducer and the shunt resistance and a rectifier and peak detection/doubler circuit. 
     
     
       11. A headset including an output reducing system according to  claim 4 . 
     
     
       12. A headset including an output reducing system according to  claim 5 . 
     
     
       13. A headset including an output reducing system according to  claim 6 . 
     
     
       14. A headset including an output reducing system according to  claim 7 . 
     
     
       15. A headset including an output reducing system according to  claim 8 . 
     
     
       16. A headset including an output reducing system according to  claim 9 . 
     
     
       17. A headset including an output reducing system according to  claim 10 .