Voice recording and playback mode using the G.726 half-rate within the personal handy phone system

• US 6,256,354 B1
• Filed: 02/20/1998
• Issued: 07/03/2001
• Est. Priority Date: 02/20/1998
• Status: Expired due to Term

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Yoshida, Satoshi, Feyfant, Patrick, Weigelt, Oliver, Lagomarsino, Rita, Winckel, Laurent, Archambaud, Denis, Gaglione, Philippe, Martin, Varenka
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US09/026,854
• Time in Patent Office: 1,229 Days
• Field of Search: 375/244, 375/219, 455/411, 455/412, 455/413
• US Class Current: 375/244
• CPC Class Codes: H04B 14/068 with adaptive feedback
• CPC Class Codes: H04M 1/6505 storing speech in digital form
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724

Abstract

Voice recording and playback mode using the G.726 half-rate within the personal handy phone system (PHS). When a portable station within the PHS operates as a voice recorder (e.g., functioning as an answering machine), a cost effective system in accordance with the present invention is adapted to compress and store received voice/sound signals in order to increase the usage of limited memory resources provided within the portable station. The present invention also enables previously compressed and stored voice/sound signals to be decompressed and played back in various portable station playback modes. Specifically, the portable station receives a voice/sound signal in a full rate (e.g., 32 kilobits-per-second) 4-bit adaptive differential pulse code modulation (ADPCM) data format in compliance with the International Telecommunication Union (ITU) recommendation G.726. The present invention compresses this received voice/sound signal to a half rate (16 kilobit-per-second) 2-bit ADPCM data format in compliance with the ITU recommendation G.726 in order to increase the usage of the limited memory resources provided within the portable station. During a playback mode of the portable station, the present invention decompresses the previously compressed and stored voice/sound signal to facilitate its playback.

Claims

1. A circuit for encoding and decoding voice signals within a portable station of a personal handy phone system, said circuit comprising:

a first receiving channel circuit coupled to receive a first voice signal over a wireless interface and for decoding said first voice signal from a first data format to a second data format;

a converter circuit coupled to receive said first voice signal in said second data format and for converting said first voice signal from said second data format to an analog data format, said converter circuit also coupled to receive a second voice signal in said analog data format and for converting said second voice signal from said analog data format to said second data format;

a first buffer device for storing said first voice signal in said second data format;

a second buffer device for storing said second voice signal in said second data format;

a controller circuit coupled to said first and second buffer devices and for mixing said first and second voice signals to produce a conversation signal in said second data format;

a third buffer device for storing said conversation signal;

a first transmitting channel circuit coupled to said third buffer device to receive said conversation signal and for encoding said conversation signal from said second data format to a third data format, said third data format being a compression of said first data format; and

a memory device coupled to said first transmitting channel circuit to receive said conversation signal and for storing said conversation signal in said third data format.

2. The circuit as described in claim 1 further comprising:

a speaker coupled to said converter circuit to receive said first voice signal in said analog data format and for rendering audible said first voice signal; and

a microphone coupled to said converter circuit and coupled to receive said second signal in said analog data format and for sending said second signal in said analog data format to said converter circuit.

3. The circuit as described in claim 1 wherein:

said first buffer device is a first-in first-out (FIFO) memory device;

said second buffer device is a first-in first-out (FIFO) memory device; and

said third buffer device is a first-in first-out (FIFO) memory device.

4. The circuit as described in claim 1 wherein:

said first receiving channel circuit is adapted to receive a third voice signal received by said portable station from said wireless interface and for decoding said third voice signal from said first data format to said second data format;

said first transmitting channel circuit is coupled to said first receiving channel circuit to receive said third voice signal in said second data format and for encoding said third voice signal from said second data format to said third data format; and

said memory device is coupled to said first transmitting channel circuit to receive said third voice signal in said third data format and is for storing said third voice signal in said third data format.

5. The circuit as described in claim 4 further comprising:

a second receiving channel circuit coupled to said memory device to receive a stored voice signal in said third data format and for decoding said stored voice signal from said third data format to said second data format; and

a second transmitting channel circuit coupled to said second receiving channel circuit to receive said stored voice signal in said second data format and for encoding said stored voice signal from said second data format to said first data format, wherein said stored voice signal in said first data format is for transmission over said wireless interface.

6. The circuit as described in claim 1 wherein said first data format is a full rate adaptive differential pulse code modulation (ADPCM) data signal.

7. The circuit as described in claim 6 wherein said second data format is a pulse code modulation (PCM) data signal.

8. The circuit as described in claim 7 wherein said third data format is a half rate adaptive differential pulse code modulation (ADPCM) data signal.

9. The circuit as described in claim 8 wherein:

said full rate adaptive differential pulse code modulation (ADPCM) data signal is 4-bits substantially complying with International Telecommunication Union (ITU) recommendation G.726 for 32 kilobits-per-second data rate;

said half rate adaptive differential pulse code modulation (ADPCM) data signal is 2-bits substantially complying with International Telecommunication Union (ITU) recommendation G.726 for 16 kilobits-per-second data rate; and

said pulse code modulation (PCM) data signal is a 14-bit linear pulse code modulation signal.

10. An apparatus for encoding and decoding voice signals within a portable station of a personal handy phone system, said apparatus comprising:

a first receiving channel means coupled to receive a first voice signal over a wireless interface and for decoding said first voice signal from a first data format to a second data format;

a converter means coupled to receive said first voice signal in said second data format and for converting said first voice signal from said second data format to an analog data format, said converter means also coupled to receive a second voice signal in said analog data format and for converting said second voice signal from said analog data format to said second data format;

a first buffer means for storing said first voice signal in said second data format;

a second buffer means for storing said second voice signal in said second data format;

a controller means coupled to said first and second buffer means and for mixing said first and second voice signals to produce a conversation signal in said second data format;

a third buffer means for storing said conversation signal;

a first transmitting channel means coupled to said third buffer means to receive said conversation signal and for encoding said conversation signal from said second data format to a third data format, said third data format being a compression of said first data format; and

a memory means coupled to said first transmitting channel means to receive said conversation signal and for storing said conversation signal in said third data format.

11. The apparatus as described in claim 10 further comprising:

a speaker coupled to said converter means to receive said first voice signal in said a nalog data format and for rendering audible said first voice signal; and

a microphone coupled to said converter means and coupled to receive said second signal in said analog data format and for sending said second signal in said analog data format to said converter means.

12. The apparatus as described in claim 10 wherein:

said first buffer means is a first-in first-out (FIFO) memory device;

said second buffer means is a first-in first-out (FIFO) memory device; and

said third buffer means is a first-in first-out (FIFO) memory device.

13. The apparatus as described in claim 10 wherein:

said first receiving channel means for receiving a third voice signal received by said portable station from said wireless interface and for decoding said third voice signal from said first data format to said second data format;

said first transmitting channel means is coupled to said first receiving channel means to receive said third voice signal in said second data format and for encoding said third voice signal from said second data format to said third data format; and

said memory means is coupled to said first transmitting channel means to receive said third voice signal in said third data format and is for storing said third voice signal in said third data format.

14. The apparatus as described in claim 13 further comprising:

a second receiving channel means coupled to said memory means to receive a stored voice signal in said third data format and for decoding said stored voice signal from said third data format to said second data format; and

a second transmitting channel means coupled to said second receiving channel means to receive said stored voice signal in said second data format and for encoding said stored voice signal from said second data format to said first data format, wherein said stored voice signal in said first data format is for transmission over said wireless interface.

15. The apparatus as described in claim 10 wherein said first data format is a full rate adaptive differential pulse code modulation (ADPCM) data signal.

16. The apparatus as described in claim 15 wherein said second data format is a pulse code modulation (PCM) data signal.

17. The apparatus as described in claim 16 wherein said third data format is a half rate adaptive differential pulse code modulation (ADPCM) data signal.

18. The apparatus as described in claim 17 wherein:

said full rate adaptive differential pulse code modulation (ADPCM) data signal is 4-bits substantially complying with International Telecommunication Union (ITU) recommendation G.726 for 32 kilobits-per-second data rate;

said half rate adaptive differential pulse code modulation (ADPCM) data signal is 2-bits substantially complying with International Telecommunication Union (ITU) recommendation G.726 for 16 kilobits-per-second data rate; and

said pulse code modulation (PCM) data signal is a 14-bit linear pulse code modulation signal.