Cellular telephone audio input compensation system and method

In a handheld cellular telephone including a transmitter for transmitting information, the information selectively including audio signals from a microphone incorporated into the telephone, the transmitter including audio circuitry to accept audio signals from the microphone and to provide amplified audio signals, and transmission circuitry to accept amplified audio signals from the audio circuitry, the transmitter audio circuitry comprising:

• a microphone audio amplifier having an input operatively connected to the output of the microphone to receive audio signals from the microphone, and an output providing an amplified audio signal for processing in subsequent transmission circuitry as part of an operative communication to the receiver of a communicating telephone, said microphone audio amplifier having a gain which is selectable to maintain the power level of the amplified audio signal within a predetermined range of power levels, and having a gain control input to which gain selection information is supplied for use in setting the gain of said microphone audio amplifier, whereby said microphone audio amplifier gain is selected to compensate for low volume input audio signal from the microphone, to provide an amplified audio signal having an improved signal to noise ratio;
• a gain controller operatively connected to said gain control input of said microphone audio amplifier for supplying gain control information to said microphone audio amplifier;
• and
• a user-operable selector operatively connected to said controller for selecting the gain of said microphone audio amplifier, whereby the signal to noise ratio of the transmitted signal carrying a low volume audio input is improved to provide the speaker of communicating telephone receiver with an increased volume audio signal.

In a telephone including a transmitter portion for transmitting information and a receiver portion for receiving information, the information selectively including audio signals from a microphone incorporated into the telephone and audio signals supplied to a speaker incorporated into the telephone and received via the receiver portion, the transmitter portion including audio circuitry to accept audio signals from the microphone and to provide amplified audio signals, and transmission circuitry to accept amplified audio signals from the audio circuitry, the telephone transmitter audio circuitry comprising:

• a microphone audio amplifier having an input operatively connected to the output of the microphone to receive audio signals from the microphone, and an output providing an amplified audio signal for processing in subsequent transmission circuitry as part of an operative communication to the receiver of a communicating telephone, said microphone audio amplifier having a gain which is selectable to maintain the power level of the amplified audio signal within a predetermined range of power levels, and having a gain control input to which gain selection information is supplied for use in setting the gain of said microphone audio amplifier, whereby said microphone audio amplifier gain is selected to compensate for a low volume input audio signal from the microphone, to provide an amplified audio signal having an improved signal to noise ratio;
• a gain controller operatively connected to said gain control input of said microphone audio amplifier for supplying gain control information to said microphone audio amplifier;
• and
• a user-operable selector operatively connected to said controller for selecting the gain of said microphone audio amplifier, said selector being operated in a manner independent of audio signals used in the receiver portion of the telephone, whereby the signal to noise ratio of the transmitted signal carrying a low volume audio input is improved to provide the speaker of communicating telephone receiver with an increased volume audio signal.

A method of compensating for a low volume voice input into the microphone of a telephone, wherein the audio signal output from the telephone transmitter audio circuitry is processed by subsequent transmission circuitry, the transmitted signal carrying the voice input as part of an operative communication with another telephone, the method comprising:

• a) providing user selectivity in the gain of a microphone audio amplifier operatively connected between the microphone of the telephone and the transmission circuitry which transmits the signal carrying the voice input;
• b) selectively increasing the gain of the microphone audio amplifier in response to a user activated input, the input being selectively activated when the user determines that the volume of the voice input is low enough to interfere with audible communication via the telephone;
• and
• c) maintaining the output of the microphone audio amplifier within a predetermined range of power levels, whereby the signal to noise ratio of the transmitted signal carrying a low volume voice input is improved to provide the speaker of communicating telephone receiver with an increased volume audio signal.

A method of compensating for a high volume voice input into the microphone of a telephone adapted for carrying audio signals at different power levels, including at least a normal audio signal level corresponding to an audio signal with a power level less than a predetermined maximum normal threshold and a high audio signal level corresponding to an audio signal with a power level greater than the maximum normal threshold, wherein the audio signal output of the telephone transmitter audio circuitry is processed by subsequent transmission circuitry, the transmitted signal carrying the voice input as part of an operative communication with another telephone, the method comprising:

• a) providing user selectivity in the gain of a microphone audio amplifier operatively connected between the microphone of the telephone and the transmission circuitry which transmits the signal carrying the audio signal;
• b) detecting the power level of the audio signal;
• and
• c) selectively decreasing the gain of the microphone audio amplifier in response to gain control input, the input being selectively activated when it is determined that the power level of the audio signal is high enough to interfere with audible communication via the telephone, the microphone audio amplifier gain selection including at least a second automatic gain selection to supply gain control information to the microphone audio amplifier as follows:
• 1) whenever the power level of the audio signal is detected to be less than the maximum normal threshold, selecting the microphone audio amplifier to be set to a first gain for use with normal audio signal levels;
• and
• 2) when the power of the audio signal is detected to be greater than the maximum normal threshold, selecting the microphone audio amplifier gain to be set in a manner inversely proportional to the power level of the audio signal for use with high audio signal levels, whereby a telephone user is automatically protected from audio signal distortion due to loud volume voice inputs.

In a handheld cellular telephone, housed in a telephone case, including a transmitter portion for transmitting information and a receiver portion for receiving information, the information selectively including audio signals from a microphone incorporated into the telephone and audio signals supplied to a speaker incorporated into the telephone and received via the receiver portion, the transmitter portion including audio circuitry to accept audio signals from the microphone and to provide amplified audio signals, and transmission circuitry to accept the amplified audio signals from the audio circuitry, the telephone transmitter audio circuitry comprising:

• a microphone audio amplifier having an input operatively connected to the output of the microphone to receive audio signals from the microphone, and an output providing an amplified audio signal for processing in subsequent transmission circuitry as part of an operative communication to the receiver of a communicating telephone, said microphone audio amplifier having a gain which is selectable to maintain the power level of the amplified audio signal within a predetermined range of power levels, and having a gain control input to which gain selection information is supplied for use in setting the gain of said microphone audio amplifier, whereby said microphone audio amplifier gain is selected to compensate for a low volume input audio signal from the microphone, to provide an amplified audio signal having an improved signal to noise ratio;
• a gain controller operatively connected to said gain control input of said microphone audio amplifier for supplying gain control information to said microphone audio amplifier;
• and
• a switch for said gain controller mounted on said case for user-operable selection of at least a normal and a high microphone audio amplifier gain, the normal gain selection being the default selection to set said microphone audio amplifier to a first gain for use with audio signals from the microphone having a power level greater than a minimum normal threshold and the high gain selection to set said microphone audio amplifier to a second gain, a predetermined amount greater than the first gain for use with audio signals from the microphone having a power level less than a minimum normal threshold, whereby the gain of said microphone audio amplifier is intermittently and selectively increased to compensate for a low-level voice input to provide the speaker of communicating telephone receiver with an increased volume audio signal.