Process and device for voice interpolation in a transmission system for digitized voice

Claim 1

A process for voice interpolation in a transmission system of digitized voice data operating in a prefiltered FSK narrow band modulation process, comprising: providing disturbance corrupted FSK demodulated information corresponding to said digitized voice data; high-pass filtering said information with a cutoff frequency at least equal to the highest frequency of the prefiltered FSK modulation band in order to provide a disturbance detection signal; deriving digitized voice data from said information; generating a predetermined pulse sequence; decoding a digital signal to produce a restored, disturbance-free voice signal; and supplying selectively said digitized voice data or said predetermined pulse sequence as said digital signal such that the presence of said disturbance detection signal causes said pulse sequence to be substituted for said digitized voice data.

Claim 3

A device for voice interpolation in a transmission system of digitized voice data by radio using prefiltered FSK modulation, comprising a reception network, a demodulation circuit coupled to said reception network having a demodulated signal output and a decoding circuit, wherein said device comprises a disturbance detection circuit in order to detect at the output of the reception network the energy received outside the modulation band comprising a high-pass filter, having a cut-off frequency at least equal to the highest frequency of the prefiltered modulation band, a threshold detector circuit coupled to the output of said high-pass filter in order to provide a disturbance detection signal and wherein said device further comprises, coupled between the demodulated signal output and the input of the decoding circuit, a switch, a first input of which is connected to the demodulated signal output and an output of which is connected to the input of the decoding circuit, a predetermined pulse sequence generator, the output of which is connected to a second input of the switch, said switch having a control input for receiving the disturbance detection signal.

Claim 4

A device for voice interpolation in a transmission system of digitized voice data by radio using prefiltered FSK modulation, comprising a reception network, a demodulation circuit coupled to said reception network having a demodulated signal output and a decoding circuit, wherein said device comprises a disturbance detection circuit in order to detect at the output of the reception network the energy received outside the modulation band comprising a high-pass filter, having a cut-off frequency at least equal to the highest frequency of the prefiltered modulation band, a threshold detector circuit coupled to the output of said high-pass filter in order to provide a disturbance detection signal and wherein said device further comprises, coupled between the demodulated signal output and the input of the decoding circuit, a switch, a first input of which is connected to the demodulated signal output and an output of which is connected to the input of the decoding circuit, a predetermined pulse sequence generator, the output of which is connected to a second input of the switch, said switch having a control input for receiving the disturbance detection signal.