EP0130431A1
Expired / Lapsed
EP
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System for digitized voice and data with means to compensate for variable path delays
Assignee: International Business Machines Corp
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Filing: 1984-06-15
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Granted: —
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Expires: 2004-06-15
Abstract
Abstract In a communications system in which voice is transmitted as packets of digitized samples, a receiving station (Fig. 3) delays the output of the first packet in a way that compensates for wide variations in the intervals at which successive packets are received. According to one feature of this system, a first packet is transmitted at a higher priority so that a greater delay can be used without encounter problems that arise from the uncertainty in the delay in transmitting this packet. In another feature of this system, the arrival times of the first few packets of a conversation are detected and the delay is readjusted in case the first packet has been unusually delayed.
Inventors
- 👤 Brian Barry Moore
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 16:28
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/64; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/062; H04J3/0632
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
167 words
A communications system of the type in which voice signals for a sending station are formed into a packet and in which packets from several sending stations are combined into a message and are transmitted to intended receiving stations, the system having alternate`pathways such that successive packets in a conversation may arrive at an intended receiving station at varying relative times, and in which the receiving station has means for delaying the output of the first packet of a conversation to compensate for variations in the delays of subsequent packets, characterized by means at the sending station for designating a message containing a first packet of a conversation to have a higher priority and for designating other messages to have a lower priority, whereby the range of delays for the first packet of a conversation is closely defined, and means (14) in a receiving station for delaying the first packet by an amount that is appropriate to a wide range of delays in the subseqent message samples.
Claim 2
Dependent Claim
167 words
A communications system of the type in which voice signals for a sending station are formed into a packet and in which packets from several sending stations are combined into a message and are transmitted to intended receiving stations, the system having alternate`pathways such that successive packets in a conversation may arrive at an intended receiving station at varying relative times, and in which the receiving station has means for delaying the output of the first packet of a conversation to compensate for variations in the delays of subsequent packets, characterized by means at the sending station for designating a message containing a first packet of a conversation to have a higher priority and for designating other messages to have a lower priority, whereby the range of delays for the first packet of a conversation is closely defined, and means (14) in a receiving station for delaying the first packet by an amount that is appropriate to a wide range of delays in the subseqent message samples.
Claim 3
Dependent Claim
64 words
The system of claim 1, the improvement including, means (14) in a receiving station for detecting the time occurrence of a few packets following the first packet, and means (14) for adjusting the time delay added to the first sample to correspond to delays encountered by the following few samples, whereby the system is adapted to a wide range of delays in subsequent samples.
Claim 4
Dependent Claim
59 words
The system of claim 2 wherein the means for detecting the relative arrival times of the next few packets after the first sample comprises, means for detecting the times of arrival of a number of packets that is typically silence at the beginning of a voice conversation, whereby the system adjusts the delay before the typical voice signal begins.
Claim 5
Dependent Claim
44 words
The system of claim 2 wherein the system comprises means (15) for buffering a small number of samples, and wherein the means for detecting the times of arrival of the next few samples comprises, means (17) for detecting an overflow of the buffering means.
Claim 6
Dependent Claim
25 words
The system of claim 4 wherein the means for detecting the times of arrives comprises means (17) for detecting an underflow of the buffering means.
Claim 7
Dependent Claim
36 words
The system of claim 4 wherein the phase of a buffer read out clock (18) is advanced, upon an overflow, so that the subsequent packets are unloaded from the buffer (15) earlier than their reference positions.
Claim 8
Dependent Claim
42 words
The system of claim 5 wherein the phase of a buffer clock (18) is retarded upon an underflow, so that the delay that otherwise would have been given to the first packet is now given to one of the first few packets.
References Cited (Backward Citations)
No citation records indexed.
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