Patent US3324537A successfully refreshed from Google Patents.
Patent EP0456914A1 successfully refreshed from Google Patents.
EP0456914A1
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Transmission quality assessment arrangement
Assignee: Nokia Bell NV
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Filing: 1990-05-15
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Granted: —
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Expires: 2010-05-15
Abstract
Abstract Transmission quality assessment arrangement for a communication switching system wherein a stream of cells of information is transmitted from an input (I) to an output (O) over a same communication path. It is adapted, at the input to insert in the cell stream test cells each having a tag indicative of its position in the resultant cell stream and to count, at the output, the position of each test cell in the latter cell stream. From the difference of the position counted and that stored in the leg of a test cell an indication of the number of added or lost cells - indicative of the transmission quality - is derived.
Inventors
- 👤 Frank Lodewijk Denissen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 23:17
CPC Classifications
H; H04; H04L; H04L43/00; H04L43/50; H04L1/00; H04L1/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
149 words
Transmission quality assessment arrangement for a communication switching system wherein a stream of cells of information is transmitted from an input (I) to an output (O) over a same communication path, characterized in that it includes : - an input circuit (CIC) associated to said input (I) and able to insert in said cell stream at least one test cell having an associated tag indicative of its position within the thus obtained resultant cell stream; - an output circuit (COC) associated to said output (O) and able to count the position of said test cell in said resultant cell stream; and - a quality ascertaining circuit (QAC) including a comparator (8) to compare the counted test cell position with the position indicated by the tag thereof and evaluation circuitry (9, 10, 11, 12) coupled to said comparator to derive from said comparison an indication of the cell transmission quality.
Claim 2
Dependent Claim
77 words
Transmission quality assessment arrangement according to claim 1, characterized in that said input circuit (CIC) includes a test cell generator (4) and a first cell counter (3) to count the cells of said resultant cell stream and to provide position indicating information (N) to said test cell generator (4) at least when a test cell has to be inserted in said cell stream, said position indicating information then constituting the position indicating tag of said test cell.
Claim 3
Dependent Claim
56 words
Transmission quality assessment arrangement according to claim 2, characterized in that said input circuit (CIC) further includes an input and multiplexer circuit (2) to respective inputs (IN, TI) of which said cell stream and said test cell are applied and whose output is coupled to said switching system input (I) via said first cell counter (3).
Claim 4
Dependent Claim
80 words
Transmission quality assessment arrangement according to claim 3, characterized in that said generator (4) allows a test cell to be inserted in said cell stream when simultaneously a free cell position is available therein as indicated by an activated output signal (F) of said input and multiplexer circuit (2) and said first cell counter (3) has counted a predetermined number of cells of said resultant cell stream, as indicated by an activated output signal (G) of said first counter (3).
Claim 5
Dependent Claim
36 words
Transmission quality assessment arrangement according to claim 2, characterized in that said generator (4) allows a test cell to be inserted in said cell stream when a predetermined time interval counted by a timer has elapsed.
Claim 6
Dependent Claim
51 words
Transmission quality assessment arrangement according to claim 2, characterized in that said first cell counter (3) has a count output (N) which is coupled to said test cell generator (4) and on which appears said position indicating information equal to the count value of said first cell counter (3) plus 1.
Claim 7
Dependent Claim
23 words
Transmission quality assessment arrangement according to claim 1, characterized in that said test cell includes an indication that it is a test cell.
Claim 8
Dependent Claim
123 words
Transmission quality assessment arrangement according to clain 1, characterized in that said output circuit (COC) includes a second cell counter (5) to count the cells of an output cell stream corresponding to said resultant cell stream and provides this count value on a count output (R) coupled to a first input (R) of said comparator (8) and a cell analyzer circuit (7) to analyze said test cell from said resultant cell stream and to provide on a first output (E) the position indicating tag thereof, said analyzer first output (E) being coupled to a second input (E) of said comparator (8) which provides the difference of the count value (R) provided by said second cell counter and that of said position indicating tag.
Claim 9
Dependent Claim
77 words
Transmission quality assessment arrangement according to claim 8, characterized in that said output circuit (COC) further includes an output and demultiplexer circuit (6) to an input of which said switching system output (O) is coupled through said second cell counter (5) and which has a first output (OUT) providing a cell stream corresponding to said cell stream and a second output (TO) which is coupled to said test cell analyzer (7) and provides said test cell thereat.
Claim 10
Dependent Claim
54 words
Transmission quality assessment arrangement according to claim 8, characterized in that said test cell analyzer (7) first output (E) is also coupled to a count input (E) of said second cell counter (5) to make the count value thereof equal to that provided at said first output (E). of said test cell analyzer (7).
Claim 11
Dependent Claim
85 words
Transmission quality assessment arrangement according to claims 8 and 9, characterized in that said comparator (8) has a first output (A) providing said difference when the latter is positive and a second output (L) providing the reverse of said difference when the latter is negative, said first (A) and second (L) comparator outputs being coupled to respective first (9) and second (11) accumulators which are operated upon a further output (T) of said analyzer circuit (7) being activated when a test cell is provided thereto.
Claim 12
Dependent Claim
58 words
Transmission quality assessment arrangement according to claim 11, characterized in that each of said accumulator outputs (QA, QL) is coupled to a threshold circuit (10, 12) which is operated when a predeteremined cell count is reached before it has been reset by a modulo counter (13) controlled from the count output (R) of said second cell counter (5).
References Cited (Backward Citations)
US4561090A
Cited
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