Communication device and method of operation

• US 6,424,822 B1
• Filed: 03/12/1999
• Issued: 07/23/2002
• Est. Priority Date: 03/13/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Cavander, Hans, Ljungberg, Per, Mekuria, Fisseha
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Nguyen, Simon
• Application Number:
  US09/267,277
• Time in Patent Office: 1,229 Days
• Field of Search: 455/72, 455/79, 455/550, 455/425, 455/285, 455/302, 455/78, 375/240, 375/241, 375/242, 375/216, 375/259, 375/262, 704/201, 704/501
• US Class Current: 455/72
• CPC Class Codes: H04M 1/6505 storing speech in digital form
• CPC Class Codes: H04M 1/72433 for voice messaging, e.g. dictaphones for answering incoming calls H04M1/64

Abstract

A communication device is provided having a speech encoder and a speech decoder and being able to retrieve and store voice messages in a memory. The messages are stored in the memory according to a message format. This format is more compressed than the speech encoding format which is provided by the speech encoder. The device includes a frame interpolation block for decompressing a stored message and thereby creating a signal according to the speech encoding format. A frame decimation block is also provided for compressing a speech encoded signal thereby allowing a corresponding voice message to be stored in the memory according to the message format.

Claims

1. An apparatus, comprising:

a controller;

a speech encoder for encoding a signal in accordance with a speech encoding format;

a code compression unit, coupled to said controller, for compressing the encoded signal in accordance with a data compression algorithm;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal; and

a switch selectively controlled by said controller to enable an encoded signal received by a receiver to be compressed by said code compression unit and stored in said memory.

2. The apparatus according to claim 1, further comprising:

a code decompression unit, coupled to said controller, for decompressing the stored signal; and

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal.

3. The apparatus according to claim 2, further comprising a switch selectively controlled by said controller to enable the stored signal to be decompressed by said decompression unit and outputted from a transceiver.

4. The apparatus according to claim 2, further comprising an operator interface unit for controlling said controller.

5. The apparatus according to claim 2, wherein said code compression unit further includes means for executing a compression operation, and said code decompression unit further includes means for executing a decompression operation.

6. The apparatus according to claim 5, wherein said compression operation and said decompression operation further includes one of a Ziv-Lempel algorithm or a Huffman algorithm.

7. The apparatus according to claim 2, wherein said code compression unit further includes means for eliminating a predetermined number of data frames from the encoded signal.

8. The apparatus according to claim 7, wherein said code decompression unit further includes means for replacing the eliminated data frames using a linear interpolation operation.

9. The apparatus according to claim 2, wherein said encoded signal comprises a plurality of data frames and said code compression unit further includes means for eliminating a plurality of bits having a low priority level from each data frame of the encoded signal.

10. The apparatus according to claim 9, wherein said code decompression unit further includes means for replacing the eliminated plurality of bits using a random code sequence.

11. The apparatus according to claim 10, Wherein said random code sequence is generated from a random code generator or a stored list of pseudo-random sequences.

12. A mobile phone, comprising:

a controller;

a microphone for receiving a signal;

a speech encoder for encoding the received signal in accordance with a speech encoding format, wherein the encoded signal comprises a plurality of data frames;

a code compression unit, coupled to said controller, for compressing the encoded signal by eliminating a plurality of bits having a low priority level from at least one of the plurality of data frames of the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal; and

a switch selectively controlled by said controller to enable an encoded signal received by a receiver to be compressed by said code compression unit and stored in said memory.

13. The mobile phone according to claim 12, further comprising:

a code decompression unit, coupled to said controller, for decompressing the stored signal;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal; and

a speaker, coupled to said speech decoder, for outputting the decoded signal.

14. The mobile phone according to claim 13, further comprising a switch selectively controlled by said controller to enable the stored signal to be decompressed by said decompression unit and outputted from a transceiver.

15. The mobile phone according to claim 13, further comprising an operator interface unit for controlling said controller.

16. The mobile phone according to claim 13, wherein said code decompression unit further includes means for replacing the eliminated plurality of bits using a random code sequence.

17. The mobile phone according to claim 16, wherein said random code sequence is generated from a random code generator or a stored list of pseudo-random sequences.

18. A method, comprising the steps of:

converting a signal to a digital signal;

encoding said digital signal in accordance with a speech encoding format;

compressing the encoded signal in accordance with a data compression algorithm;

storing the compressed encoded signal;

decompressing the stored signal by replacing an eliminated set of data using a random code sequence generated by using a random code generator or using a stored list of pseudo-random sequences.

decoding the decompressed signal; and

outputting the decoded signal.

19. The method according to claim 18, wherein said step of decompressing further includes replacing eliminated data frames using a linear interpolation method.

20. The method according to claim 18, further comprising the steps of:

decompressing the stored signal; and

transmitting the decompressed signal from a transmitter.

21. The method according to claim 18, wherein said step of compressing further includes eliminating a predetermined number of data frames from the encoded signal.

22. The method according to claim 18, wherein said encoded signal comprises a plurality of data frames and said step of compressing further includes eliminating a plurality of bits having a low priority level from each of the plurality of data frames of the encoded signal.

23. The method according to claim 18, wherein said step of compressing further includes executing a Ziv-Lempel algorithm or a Huffman algorithm.

24. The method according to claim 18, further comprising the steps of:

receiving an encoded signal from a receiver;

compressing the received signal; and

storing the compressed received signal.

25. An apparatus, comprising:

a receiver for receiving an encoded speech signal, said encoded speech signal encoded according to a speech encoding format;

a compression unit, coupled to said receiver, for compressing said encoded speech signal;

a memory unit, coupled to said compression unit, for storing the compressed speech encoded signal, the compressed speech encoded signal compressed according to a message data format; and

a switch to enable an encoded signal received by said receiver to be compressed by said compression unit and stored in said memory.

26. The apparatus of claim 25, further comprising:

a decompression unit, coupled to said memory unit, for decompressing the compressed speech encoded signal to recover said speech encoded signal;

a speech decoder, coupled to said decompression unit, for decoding said speech encoded signal; and

a speaker, coupled to said speech decoder, for outputting the decoded signal.

27. An apparatus, comprising:

a controller;

a speech encoder for encoding a signal;

a code compression unit, coupled to said controller, for compressing the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal; and

a switch selectively controlled by said controller to enable an encoded signal received by a receiver to be compressed by said code compression unit and stored in said memory.

28. An apparatus, comprising:

a controller;

a speech encoder for encoding a signal;

a code compression unit, coupled to said controller, for compressing the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal; and

a switch selectively controlled by said controller to enable the stored signal to be decompressed by said decompression unit and outputted from a transceiver.

29. An apparatus, comprising:

a controller;

a speech encoder for encoding a signal;

a code compression unit, coupled to said controller, for compressing the encoded signal, said code compression unit further including means for eliminating a set of data having a low priority level from the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal, said code decompression unit further including means for replacing the eliminated set of data using a random code sequence; and

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal.

30. The apparatus according to claim 29, wherein said random code sequence is generated from a random code generator or a stored list of pseudo-random sequences.

31. A mobile phone, comprising:

a controller;

a microphone for receiving a signal;

a speech encoder for encoding the received signal;

a code compression unit, coupled to said controller, for compressing the encoded signal by eliminating a set of data having a low priority level from the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal;

a speaker, coupled to said speech decoder, for outputting the decoded signal; and

a switch selectively controlled by said controller to enable an encoded signal received by a receiver to be compressed by said code compression unit and stored in said memory.

32. A mobile phone, comprising:

a controller;

a microphone for receiving a signal;

a speech encoder for encoding the received signal;

a code compression unit, coupled to said controller, for compressing the encoded signal by eliminating a set of data having a low priority level from the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal;

a speaker, coupled to said speech decoder, for outputting the decoded signal; and

a switch selectively controlled by said controller to enable the stored signal to be decompressed by said decompression unit and outputted from a transceiver.

33. A mobile phone, comprising:

a controller;

a microphone for receiving a signal;

a speech encoder for encoding the received signal;

a code compression unit, coupled to said controller, for compressing the encoded signal by eliminating a set of data having a low priority level from the encoded signal;

a memory, coupled to an output of said code compression unit, for storing the compressed encoded signal;

a code decompression unit, coupled to said controller, for decompressing the stored signal by replacing the eliminated set of data using a random code sequence;

a speech decoder, coupled to said code decompression unit, for decoding the decompressed signal; and

a speaker, coupled to said speech decoder, for outputting the decoded signal.

34. The mobile phone according to claim 33, wherein said random code sequence is generated from a random code generator or a stored list of pseudo-random sequences.

35. A method, comprising the steps of:

converting a signal to a digital signal;

encoding said digital signal;

compressing the encoded signal;

storing the compressed encoded signal;

decompressing the stored signal by replacing an eliminated set of data using a random code sequence;

decoding the decompressed signal; and

outputting the decoded signal.

36. The method according to claim 35, further comprising the step of generating the random code sequence using a random code generator or using a stored list of pseudo-random sequences.