Method of transmitting an audio signal

Claim 1

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of the first digital signal in the respective time segments into respective second digital signals representing the respective short-term spectrums of the time segments; encoding the second digital signals for transmission while omitting from encoding portions of said second signals having signal levels which lie below given thresholds having values based on the psycho-acoustic law of masking, and such that the portions of the second signals having signal levels which are below the thresholds and are thus omitted, represent the frequency components of the short-term spectrum outside of at least one psycho-acoustically differentiable frequency range; and transmitting the encoded second signals.

Claim 2

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of the first digital signal in the respective time segments into respective second digital signals representing the respective short-term spectrums of the time segments; encoding the second digital signals for transmission while omitting from encoding portions of said second signals having signal levels which lie below given thresholds having values based on the psycho-acoustic law of masking, and such that the portions of the second signals having signal levels which are below the thresholds and are thus omitted, represent the frequency components of the short-term spectrum outside of at least one psycho-acoustically differentiable frequency range; and transmitting the encoded second signals.

Claim 15

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of teh first digital signal in the respective time segments, the entire frequency range digital signals representing the respective short-term spectrums of the time segments, the entire frequency range of the short-term spectrum being divided into psycho-accoustically differentiable frequency groups which each include at least one spectral component; establishing a first threshold individually for each group, the first threshold for each group being defined by the logarithmed ratio of the effective value of the maximum level of the spectral components of the group to the square root of the mean energy of all spectral components of the group, multiplied by a constant factor, establishing for each group having a spectral component in a frequency range below a given frequency, a second threshold which is lower than the first threshold established for the group; encoding the second digital signals for transmission while in the groups having spectral components in the frequency ranges above the given frequency, omitting from encoding portions of the second signals which lie below the first thresholds and including in the encoding portions which lie above the second thresholds, and in the groups having spectral components in the frequency ranges below the given frequency, further omitting from encoding portions of the second signals which lie below the second thresholds and including in the encoding portions which lie above the second thresholds; and transmitting the encoded second signals.

Claim 16

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of teh first digital signal in the respective time segments, the entire frequency range digital signals representing the respective short-term spectrums of the time segments, the entire frequency range of the short-term spectrum being divided into psycho-accoustically differentiable frequency groups which each include at least one spectral component; establishing a first threshold individually for each group, the first threshold for each group being defined by the logarithmed ratio of the effective value of the maximum level of the spectral components of the group to the square root of the mean energy of all spectral components of the group, multiplied by a constant factor, establishing for each group having a spectral component in a frequency range below a given frequency, a second threshold which is lower than the first threshold established for the group; encoding the second digital signals for transmission while in the groups having spectral components in the frequency ranges above the given frequency, omitting from encoding portions of the second signals which lie below the first thresholds and including in the encoding portions which lie above the second thresholds, and in the groups having spectral components in the frequency ranges below the given frequency, further omitting from encoding portions of the second signals which lie below the second thresholds and including in the encoding portions which lie above the second thresholds; and transmitting the encoded second signals.

Claim 26

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of the first digital signal in the respective time segments into respective second digital signals representing the respective short-term spectrums of the time segments; encoding the second digital signals for transmission while omitting from encoding portions of said second signals having signal levels which lie below given thresholds having values based on the psycho-acoustic law of masking, and such that the portions of the second signals having signal levels which are below the thresholds and are thus omitted, represent the frequency components of the short-term spectrum outside of a psycho-acoustically differentiable frequency range which includes spectral components in a vicinity of the frequency component having the absolute maximum level of the short-term spectrum, one of the thresholds being defined in the psycho-acoustically differentiable frequency range said step of encoding including the step of encoding the spectral components which lie within the psycho-acoustically differentiable frequency range and which have signal levels above and below the one of the thresholds and transmitting the encoded second signals.

Claim 27

A method of transmitting an analog audio signal in digital form to be reconverted to analog form, comprising the steps of: converting an analog audio signal to a first digital signal; dividing the first digital signal in time segments; converting divided portions of the first digital signal in the respective time segments into respective second digital signals representing the respective short-term spectrums of the time segments; encoding the second digital signals for transmission while omitting from encoding portions of said second signals having signal levels which lie below given thresholds having values based on the psycho-acoustic law of masking, and such that the portions of the second signals having signal levels which are below the thresholds and are thus omitted, represent the frequency components of the short-term spectrum outside of a psycho-acoustically differentiable frequency range which includes spectral components in a vicinity of the frequency component having the absolute maximum level of the short-term spectrum, one of the thresholds being defined in the psycho-acoustically differentiable frequency range said step of encoding including the step of encoding the spectral components which lie within the psycho-acoustically differentiable frequency range and which have signal levels above and below the one of the thresholds and transmitting the encoded second signals.