US3770894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic transmission line testing system
Assignee: AT&T Inc
•
Filing: 1972-09-25
•
Granted: 1973-11-06
•
Expires: 1992-09-25
Abstract
Abstract A time assignment speech interpolation system is disclosed utilizing time-shared common control processing circuits. Speech signals from a plurality of trunks are interpolated on a lesser plurality of long-haul transmission channels by connecting trunks only during active periods. In order to detect channel failures rapidly, each channel is automatically tested in a sequence by transmitting a test tone preceded and followed by a silent period. Channel delay is measured during the initial silent period. Transmission gain is measured during the test tone and noise is measured during the terminal silent period. Priority checking is provided for channels about to be restored to service and for channels which have failed once.
Inventors
- 👤 C May
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:03
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/17; H04J3/02; H04J3/14
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
117 words
A testing arrangement for multichannel communication systems comprising a source of test tone, means in said test tone source for generating said test tone in a testing period in which the tone is preceded by a timed silent period and followed by a timed silent period, means for selectively and sequentially connecting said source to the channels of said communication system, means for measuring the delay between the start of said test period and the receipt of said test tone, means for measuring the transmission level of said test tone, means for measuring the noise level in said following silent interval, and means for recording the parameters measured by said aforementioned measuring means for each said channel.
Claim 2
Dependent Claim
117 words
A testing arrangement for multichannel communication systems comprising a source of test tone, means in said test tone source for generating said test tone in a testing period in which the tone is preceded by a timed silent period and followed by a timed silent period, means for selectively and sequentially connecting said source to the channels of said communication system, means for measuring the delay between the start of said test period and the receipt of said test tone, means for measuring the transmission level of said test tone, means for measuring the noise level in said following silent interval, and means for recording the parameters measured by said aforementioned measuring means for each said channel.
Claim 3
Dependent Claim
37 words
The testing arrangement according to claim 1 wherein said communication system comprises a time assignment speech interpolation system, and said means for selectively connecting said source comprises the interpolation switches of said time assignment speech interpolation system.
Claim 4
Dependent Claim
56 words
The testing arrangement according to claim 1 wherein said means for selectively connecting said source includes means for storing an identification code for a first one of said channels, means responsive to said identification code for enabling said selective connecting means, and means responsive to the termination of said testing period for incrementing said identification code.
Claim 5
Dependent Claim
66 words
The testing arrangement according to claim 1 wherein said means for measuring delay comprises a counter, means for entering a preselected count into said counter to represent the minimum possible delay of said channels, means for advancing said counter at regular timed iNtervals following the start of said testing period, and means for reading out the contents of said counter upon receipt of said test tone.
Claim 6
Dependent Claim
50 words
The testing arrangement according to claim 1 further including timing means, means responsive to said timing means for sampling said test tone at substantially the center thereof, and means responsive to said timing means for enabling said noise level measuring means substantially in the center of said following silent interval.
Claim 7
Dependent Claim
46 words
The testing arrangement according to claim 1 wherein said means for recording parameters comprises a storage arrangement for storing said parameters for each of said channels, and means for transferring said parameters from said various measuring means to said storage means following each set of measurements.
Claim 8
Dependent Claim
133 words
An automatic channel testing system comprising a plurality of transmission channels, a signal source including gating means for interposing a timed test signal between two timed silent periods in a testing interval, means for selectively connecting said signal source to each one of a plurality of transmission channels in sequence, said connecting means including means for skipping those ones of said channels which are currently not in service, and means for delaying the connection of each said channel until that channel is no longer being used, means for measuring the transit time delay of each channel during a first one of said silent periods, means for measuring the noise level of each said channel during the other one of said silent periods, and means for measuring the transmission level of said test tone.
Claim 9
Dependent Claim
133 words
An automatic channel testing system comprising a plurality of transmission channels, a signal source including gating means for interposing a timed test signal between two timed silent periods in a testing interval, means for selectively connecting said signal source to each one of a plurality of transmission channels in sequence, said connecting means including means for skipping those ones of said channels which are currently not in service, and means for delaying the connection of each said channel until that channel is no longer being used, means for measuring the transit time delay of each channel during a first one of said silent periods, means for measuring the noise level of each said channel during the other one of said silent periods, and means for measuring the transmission level of said test tone.
Claim 10
Dependent Claim
41 words
The automatic testing system according to claim 7 further including delay timing means, and means responsive to said delay timing mans for lengthening each testing cycle of said testing system to prevent excessive interference with normal transmissions on said transmission channels.
Claim 11
Dependent Claim
44 words
The automatic testing system according to claim 7 further including a priority check initiating circuit, means in said circuit for selectively testing channels marked for priority testing, and means for marking for priority checking those ones of said channels previously exhibiting undesirable test parameters.
Claim 12
Dependent Claim
31 words
The automatic testing system according to claim 9 further including means for selectively identifying transmission channels to be restored to service, and means for marking said identified channels for priority testing.
Claim 13
Dependent Claim
99 words
A transmission channel testing system comprising means for sequentially removing each of a plurality of transmission channels from active use for testing purposes, means for transmitting a timed signal burst preceded by and followed by silent periods on each said channel so removed from service, means for measuring the channel delay of each of said channels during the silent period preceding said signal burst, means for measuring the transmission level of each of said channels during said signal burst, and means for measuring the channel noise of each of said channels during said silent period following said signal burst.
Claim 14
Dependent Claim
99 words
A transmission channel testing system comprising means for sequentially removing each of a plurality of transmission channels from active use for testing purposes, means for transmitting a timed signal burst preceded by and followed by silent periods on each said channel so removed from service, means for measuring the channel delay of each of said channels during the silent period preceding said signal burst, means for measuring the transmission level of each of said channels during said signal burst, and means for measuring the channel noise of each of said channels during said silent period following said signal burst.
Claim 15
Dependent Claim
35 words
The transmission channel testing system according to claim 11 further including a time assignment speech interpolation system, and said means for sequentially removing channels comprises the interpolation switches of said time assignment speech interpolation system.
Claim 16
Dependent Claim
59 words
The transmission channel testing system according to claim 11 wherein said means for sequentially removing channels includes means for storing an identification code for a first one of said transmission channels, means responsive to said identification code for enabling said sequential removing means, and means responsive to the termination of said following silent period for incrementing said identification code.
Claim 17
Dependent Claim
71 words
The transmission channel testing system according to claim 11 wherein said means for measuring Channel delay comprises a counter, means for entering preselected count into said counter to represent the minimum possible delay of said transmission channels, means for advancing said counter at regular timed intervals following the start of said preceding silent period, and means for reading out the contents of said counter upon receipt of said timed signal burst.
Claim 18
Dependent Claim
53 words
The transmission channel testing system according to claim 11 further including timing means, means responsive to said timing means for sampling said timed signal burst at substantially the center thereof, and means responsive to said timing means for enabling said channel noise measuring means substantially in the center of said following silent interval.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |