Data processing: speech signal processing – linguistics – language – Speech signal processing – For storage or transmission
Reexamination Certificate
1998-08-18
2001-01-09
{circumflex over (S)}mits, T{overscore (a)}livaldis I. (Department: 2741)
Data processing: speech signal processing, linguistics, language
Speech signal processing
For storage or transmission
Reexamination Certificate
active
06173254
ABSTRACT:
BACKGROUND
Certain mobile phone systems use a memory unit for storing a voice message from a user such as an outgoing voice message. The user can store their personalized voice message in that memory. The message is played back as the user's personalized message. That memory unit has a limited size. However, the user often wants to store a longer message.
Speech is often compressed before storing in this memory. Speech can be compressed using a well-known voice coder or vocoder system. Vocoders are well known in the art and compresses the speech by using well-known models. These models typically compress the speech based on its different parts: silence, noise and actual utterances. Codebooks are used to compress the different components of the speech.
A well-known and often-used system compresses the speech using variable rate coding. Several different standards exist. The Enhanced Variable Rate Coding (“EVRC”) from Telecommunications Industries Association (TIA) is one. Cellular carriers in Japan including DDI and IDO have decided to adopt EVRC. Qualcomm also has a system called the Qualcomm Code Excluded Linear Predictive Coder (“QCELP”).
A basic description of such variable rate codecs is found in U.S. Pat. No. 5,495,555, the disclosure of which is incorporated by reference to the extent necessary for proper understanding.
All of these systems operate an algorithm that determines an optimal encoding rate to use depending on the voice power.
The rate can be encoded at one-eighth maximum rate for much of the signal. Other parts of the signal can be encoded at one-quarter, one-half, and/or full voice power as shown. Again, the algorithm determines this coding. By reducing the maximum voice power that is encoded, the system saves on bandwidth.
SUMMARY OF THE INVENTION
The variable rate system codes the greeting message based on the amount of voice power in the greeting. However, at certain times, base station may require a rate reduction which limits the maximum full rate of the system. This rate reduction is detailed in various standards, including EIA/TIA/IS-127. One common reason for the command for rate reduction is too much traffic on the system. The system responds by changing the maximum duty cycle of the frames. Hence, the system carries less data during these times.
The inventor recognized that if the greeting message is already recorded at a different rate than that specified by the system, a conflict may exist. For example, if the message has portions recorded at full rate, there might be difficulties if the base station commands half-rate maximum.
REFERENCES:
patent: Re. 34976 (1995-06-01), Helferich et al.
patent: 4864301 (1989-09-01), Helferich
patent: 5003576 (1991-03-01), Helferich
patent: 5133010 (1992-07-01), Borth et al.
patent: 5414796 (1995-05-01), Jacobs et al.
patent: 5495555 (1996-02-01), Swaminathan
patent: 5657420 (1997-08-01), Jacobs et al.
patent: 5737716 (1998-04-01), Bergstrom et al.
patent: 5796757 (1998-08-01), Czaja
Denso Corporation, Ltd.
Fish & Richardson PC
Wieland Susan
{circumflex over (S)}mits T{overscore (a)}livaldis I.
LandOfFree
Recorded message playback system for a variable bit rate system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Recorded message playback system for a variable bit rate system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recorded message playback system for a variable bit rate system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512439