Patent ID: 7624022

Claim:
A speech compression apparatus comprising: a first band-transform unit transforming a wideband speech signal to a narrowband low-band speech signal; a narrowband speech compressor compressing the narrowband low-band speech signal and outputting a result of the compressing as a low-band speech packet; a decompression unit decompressing the low-band speech packet and obtaining a decompressed wideband low-band speech signal; an error detection unit detecting an error signal that corresponds to a difference between the wideband speech signal and the decompressed wideband low-band speech signal; and a high-band speech compression unit compressing the error signal and a high-band speech signal of the wideband speech signal and outputting the result of the compressing as a high-band speech packet, wherein the error detection unit comprises: a first filter bank filtering the wideband speech signal in a first specified frequency band and outputting a first filtered signal; a first half-wave rectifier performing half-wave rectification for the first filtered signal and outputting a first half-wave rectified signal; a first peak detector detecting a first peak signal from the first half-wave rectified signal; a first masking unit generating a first masked signal for the wideband speech signal from the first peak signal; a second filter bank filtering the decompressed wideband low-band speech signal in a second specified frequency band and outputting a second filtered signal; a second half-wave rectifier performing half-wave rectification for the second filtered signal and outputting a second half-wave rectified signal; a second peak detector detecting a second peak signal from the second half-wave rectified signal; a second masking unit generating a second masked signal for the decompressed wideband low-band speech signal from the second peak signal; and an inter-signal masking unit performing inter-signal masking on the first and second masked signals.