High fidelity speech encoding for telecommunications systems
First Claim
1. A telephone for producing and receiving audible speech sound having no foldover distortion owing to the natural frequency spectrum of vowel sounds and having no lowpass filter, said telephone comprising:
- a microprocessor;
first transducer means for producing, transmitting and receiving signals representing audible speech sound; and
signal processing means coupled to the microprocessor and to the transducer means, for converting said audible speech sound to digital signals having a predetermined data rate, said data rate including a preselected sampling rate and a preselected digitizing rate;
said preselected sampling rate selected at a rate for no foldover distortion of said vowel sounds and said preselected sampling rate is less than the Nyquist sampling rate of consonant sounds found in said audible speech sound;
said signal processing means including volume compression means for compressing said audible speech sound;
said preselected digitizing rate selected for use with said volume compression means for reducing quantization noise;
said preselected sampling rate and said preselected digitizing rate cooperating to provide high fidelity speech quality;
said signal processing means further including error correction means for producing digital signals representing error correction code at a preselected rate and for combining said last-mentioned digital signals with said digital signals representing audible speech sound;
said signal processing means further including conversion means for converting digital signals representing said audible speech sound to speech signals representing said audible speech sound.
0 Assignments
0 Petitions
Accused Products
Abstract
A user-orientated telephone instrument including high-fidelity speech encoding, encryption capability and many function presently provided by centralized call processing is described. Utilizing an ADPCM encoding process including forward error correction, a high quality relatively noise immune signal is provided. To the user, the instrument appears as a unique electronic telephone which offers many special services to facilitate communications with other people and with computers. Advanced features such as optional hands-off voice on/off-hook control, personal identification by voice print and remote chart presentation are provided.
-
Citations
5 Claims
-
1. A telephone for producing and receiving audible speech sound having no foldover distortion owing to the natural frequency spectrum of vowel sounds and having no lowpass filter, said telephone comprising:
-
a microprocessor; first transducer means for producing, transmitting and receiving signals representing audible speech sound; and signal processing means coupled to the microprocessor and to the transducer means, for converting said audible speech sound to digital signals having a predetermined data rate, said data rate including a preselected sampling rate and a preselected digitizing rate; said preselected sampling rate selected at a rate for no foldover distortion of said vowel sounds and said preselected sampling rate is less than the Nyquist sampling rate of consonant sounds found in said audible speech sound; said signal processing means including volume compression means for compressing said audible speech sound; said preselected digitizing rate selected for use with said volume compression means for reducing quantization noise; said preselected sampling rate and said preselected digitizing rate cooperating to provide high fidelity speech quality; said signal processing means further including error correction means for producing digital signals representing error correction code at a preselected rate and for combining said last-mentioned digital signals with said digital signals representing audible speech sound; said signal processing means further including conversion means for converting digital signals representing said audible speech sound to speech signals representing said audible speech sound. - View Dependent Claims (2, 3, 4, 5)
-
Specification