Patent ID: 6070088
Filing Date: 2000-05-30
Classification: H03G,H04M

Abstract:
A portable telephone set comprising:an audio-frequency amplifier amplifying sound signals from a microphone;a codec digitizing and coding said sound signals into digital sound signals;a digital signal processor monitoring levels of said sound signal to produce detected levels;a memory storing preset sound level data; andsound level controlling means for averaging the detected levels and comparing the average to said preset sound level data stored in said memory to control amplification of at least one of said audio-amplifier and said codec,wherein said sound level controlling means comprises,timer means for producing a timing signal at a predetermined time interval,a processor unit storing said detected levels into said memory, said processor unit being responsive to said timing signal to average said detected levels stored in said memory to produce an averaged level and comparing said averaged level with said preset sound level data to produce an error level, said processor unit producing an amplification control signal corresponding to said error level, andgain control means responsive to said amplification control signal for controlling said amplification degree of at least one of said audio-amplifier and said codec, andwherein said codec comprises,a prefilter for passing said sound signals from said audio-frequency amplifier,an analog/digital converter for digitizing said sound signals into said digital signals,a digital gain controller for controlling a gain of said digital sound signals, anda bandpass filter for passing said digital sound signals.