US4710969A
Expired / Lapsed
US
⏱️ 0.0 years remaining
CATV testing system
Assignee: Acterna LLC
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Filing: 1981-12-01
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Granted: 1987-12-01
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Expires: 2001-12-01
Abstract
Abstract Signal quality in a cable in a particular frequency range is monitored and analyzed without interfering with the cable reception of CATV signals. Carrier signals at a transmitter are modulated with a pair of pass signals separated in time by a television frame period. Preferably before the first pass signal in the pair, a series of digital signals is provided indicating the parameters of a frequency sweep which is initiated upon the occurrence of the second pass signal. These parameters include the sweep start frequency, the sweep frequency bandwidth, the sweep duration and the sweep repetition rate. A frequency sweep according to such parameters is produced when the second pass signal occurs. The modulated carrier signals are transmitted through the cable to a receiver coupled to the cable. The receiver demodulates the carrier signals and processes the series of digital signals to determine the sweep signal parameters. When the first pass signal occurs, the CATV television signals in the cable pass to the receiver. When the second pass signal occurs, the television signals in the next cable frame also pass to the receiver for subtraction from the first CATV signals. Since these two signals are substantially the same, they are canceled. When the second pass signal occurs, the receiver receives the frequency sweep from the transmitter. These signals are stored in a digital memory for recirculation to a display. In this way, the quality of a transmission medium is determined and displayed without affecting the television signal quality in the medium.
Inventors
- 👤 Sydney Fluck, Jr.
- 👤 Marvin L. Milholland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:24
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/46
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
203 words
In combination for use at a receiver for monitoring and analyzing the quality of signals passing through a cable in successive television frame times where television signals for the successive time frames are passed through the cable and digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and where first and second pass signals are provided in the cable to define successive frame times and where sweep signals are provided in the cable in synchronism with the second pass signal in the pair and where the digital signals, the pass signals and the sweep signals are transmitted through the cable to the receiver, first means for recovering the pass signals, the sweep signals, the digital signals and the television signals in the successive frames, second means for storing representations of the recovered signals in the successive frame times, third means responsive to the second pass signal for passing the representations of the recovered signals from the second means, and fourth means responsive to the recovered signals from the first means and the representations of the recovered signals from the third means for subtracting such recovered signals to recover the sweep signals.
Claim 2
Dependent Claim
203 words
In combination for use at a receiver for monitoring and analyzing the quality of signals passing through a cable in successive television frame times where television signals for the successive time frames are passed through the cable and digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and where first and second pass signals are provided in the cable to define successive frame times and where sweep signals are provided in the cable in synchronism with the second pass signal in the pair and where the digital signals, the pass signals and the sweep signals are transmitted through the cable to the receiver, first means for recovering the pass signals, the sweep signals, the digital signals and the television signals in the successive frames, second means for storing representations of the recovered signals in the successive frame times, third means responsive to the second pass signal for passing the representations of the recovered signals from the second means, and fourth means responsive to the recovered signals from the first means and the representations of the recovered signals from the third means for subtracting such recovered signals to recover the sweep signals.
Claim 3
Dependent Claim
54 words
The combination set forth in claim 1 wherein the fourth means is coupled to the second means to introduce to the second means the sweep signals recovered by the fourth means, and means are included for averaging on a weighted basis the sweep signals introduced to the second means in the successive frame times.
Claim 4
Dependent Claim
37 words
The combination set forth in claim 2 wherein the first means includes means for performing checks of parity and sums on the serial digital signals before the operation of the fourth means in recovering the sweep signals.
Claim 5
Dependent Claim
62 words
The combination set forth in claim 1 wherein the second means is operative only during the period between the first and second pass signals and the fourth means is operative for a particular period of time after the production of the second pass signal where such particular period is at least equal to the period for the production of the sweep signals.
Claim 6
Dependent Claim
54 words
The combination set forth in claim 4, including, gate means associated with the second means for passing the stored representations of the recovered signals for each of the successive frame time in synchronism with the introduction of the representations of the recovered signals from the third means for each of the successive frame times.
Claim 7
Dependent Claim
48 words
The combination set forth in claim 1 wherein the fourth means is operative to receive the signals from the first means in each of the successive frame times in synchronism with the recovered representations of the signals from the third means for each of the successive frame times.
Claim 8
Dependent Claim
233 words
In combination for use at a receiver for monitoring and analyzing the quality of signals passing through a cable in successive television frame times where television signals for the successive frame times are passed through the cable and digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and first and second pass signals are provided in the cable to indicate successive frame times of the signals and a sweep signal is provided in the cable in synchronism with the second pass signal, first means responsive to the serial digital signals for providing a parity check, second means responsive to the parity check and the first pass signal in each pair for providing a representation of the television signals from the cable in first frame times, third means responsive to the parity check and the second pass signal in each pair for providing representations of the television and sweep signals from the cable in second frame times subsequent to the first frame times, and means responsive to the signals from the second and third means for comparing the reresentations of signals from the second and third means in the first and second frame times to obtain a cancellation of the television signals from the second and third means in the first and second frame times and a recovery of the sweep signals.
Claim 9
Dependent Claim
233 words
In combination for use at a receiver for monitoring and analyzing the quality of signals passing through a cable in successive television frame times where television signals for the successive frame times are passed through the cable and digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and first and second pass signals are provided in the cable to indicate successive frame times of the signals and a sweep signal is provided in the cable in synchronism with the second pass signal, first means responsive to the serial digital signals for providing a parity check, second means responsive to the parity check and the first pass signal in each pair for providing a representation of the television signals from the cable in first frame times, third means responsive to the parity check and the second pass signal in each pair for providing representations of the television and sweep signals from the cable in second frame times subsequent to the first frame times, and means responsive to the signals from the second and third means for comparing the reresentations of signals from the second and third means in the first and second frame times to obtain a cancellation of the television signals from the second and third means in the first and second frame times and a recovery of the sweep signals.
Claim 10
Dependent Claim
36 words
The combination set forth in claim 7, including, means responsive to the sweep signals for providing a visual indication of the quality of response of the cable to signals at the different frequencies in the sweep.
Claim 11
Dependent Claim
30 words
The combination set forth in claim 8 wherein means are included for providing visual indications of the quality of response of the cable in any particular portion of the sweep.
Claim 12
Dependent Claim
65 words
The combination set forth in claim 9, including, means for storing the representations of the television signals in the first frame times, and gate means operatively coupled to the storing means for synchronizing the introduction to the comparing means of the representation of the television signals in the first frame times and the representation of the television and sweep signals in the second frame times.
Claim 13
Dependent Claim
38 words
The combination set forth in claim 8 wherein means are included for storing the respresentations of the television signals in digital form and wherein such digital signals are recirculated and are converted into analog form in each recirculation.
Claim 14
Dependent Claim
45 words
The combination set forth in claim 8, including, gate means operative to synchronize the introduction to the comparing means of the representations of the television signals in the first frame times and the representations of the television and sweep signals in the second frame times.
Claim 15
Dependent Claim
264 words
In combination at a receiver for monitoring and analyzing the quality of telelvision signals passing through a cable in successive television frame times where digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and first and second pass signals are provided in the cable upon each production of the digital signals to indicate successive time frames of the signals and a sweep signal is provided in the cable upon the occurrence of the first and second pass signals. first means for detecting the signals in the cable to receive the television signals, the digital signals and the pass signals, second means responsive to the digital signals for providing a parity and sum check, third means responsive to the parity and sum check and the first pass signal for passing the television signals from the cable in first frame times after the production of the first pass signal, fourth means responsive to the parity and sum check and the second pass signal for providing the television and sweep signals from the cable in second frame times after the first frame times and after the production of the second pass signal, fifth means responsive to the signals from the third and fourth means for obtaining the difference between such signals to recover the sweep signals from the fourth means, and sixth means responsive to the recovered sweep signals for processing such recovered sweep signals to provide an indication of the quality of the signals in the cable at the different frequencies in the sweep.
Claim 16
Dependent Claim
264 words
In combination at a receiver for monitoring and analyzing the quality of telelvision signals passing through a cable in successive television frame times where digital signals are provided in the cable in serial form to represent information relating to the parameters of a frequency sweep and first and second pass signals are provided in the cable upon each production of the digital signals to indicate successive time frames of the signals and a sweep signal is provided in the cable upon the occurrence of the first and second pass signals. first means for detecting the signals in the cable to receive the television signals, the digital signals and the pass signals, second means responsive to the digital signals for providing a parity and sum check, third means responsive to the parity and sum check and the first pass signal for passing the television signals from the cable in first frame times after the production of the first pass signal, fourth means responsive to the parity and sum check and the second pass signal for providing the television and sweep signals from the cable in second frame times after the first frame times and after the production of the second pass signal, fifth means responsive to the signals from the third and fourth means for obtaining the difference between such signals to recover the sweep signals from the fourth means, and sixth means responsive to the recovered sweep signals for processing such recovered sweep signals to provide an indication of the quality of the signals in the cable at the different frequencies in the sweep.
Claim 17
Dependent Claim
74 words
The combination set forth in claim 13 wherein seventh means are included for weighting the recovered sweep signals in a particular relationship through at least a pair of the successive television frame times and wherein the sixth means are responsive to the weighted signals for processing such signals to eliminate the effect of noises in providing an indication of the quality of the signals in the cable at the different frequencies in the sweep.
Claim 18
Dependent Claim
78 words
The combination set forth in claim 14 wherein the third means are operative only in the period between the first and second pass signals to pass the television signals in the cable and wherein means are included in the third means for storing the representation of such signals to introduce such representation of such signals to the fifth means in synchronism with the introduction of the television and sweep signals by the fourth means to the fifth means.
Claim 19
Dependent Claim
50 words
The combination set forth in claim 15, including, gate means responsive to the second pass signal and the television signals from the third means for introducing such television signals to the fifth means in synchronism with the television and sweep signals introduced from the fourth means to the fifth means.
Claim 20
Dependent Claim
63 words
The combination set forth in claim 13 wherein means are included for converting to digital form the television signals provided by the third means and for storing such digital signals and for recirculating such stored signals and converting such recirculated signals to analog form for introduction to the fifth means in synchronism with the television and sweep signals provided by the fourth means.
Claim 21
Dependent Claim
44 words
The combination set forth in claim 17 wherein the fifth means include means for providing a visual display of the recovered sweep signals, and means for directing attention in the visual display to the recovered sweep signals in individual portions of the visual display.
Claim 22
Dependent Claim
300 words
In combination for monitoring and analyzing the quality of a cable in transmitting television signals through the cable in successive television frame times, means for providing carrier signals, means for providing control information indicative of a sweep between a particualr start frequency and a particular stop frequency in a particular time duration and at a particular repetition rate, means for converting the control information into serial digital data and for providing first and second pass signals representing in time separation the passage of the television signals through the cable in the successive television frame times, means for producing a sweep signal upon the production of the second pass signal and in accordance with the control information, means for combining the carrier signals with the digital data in serial form and with the pass signals and the sweep signals for introducing such combined signals into the television cable, means for receiving the combined signals passing through the television cable, means for demodulating the received signals to recover the digital data in serial form and the pass signals, means for processing the recovered serial digital data to provide a parity and sum check, means responsive to the parity and sum check and the first pass signal for passing the television signals in the cable in the television frame time between the pass signals, means responsive to the parity and sum check and the second pass signal for passing the television and sweep signals in the frame after each such second pass signal, and mean responsive to the operation of the last two mentioned means for comparing the signals from such last two mentioned means to recover the sweep signals in the cable for obtaining an indication of the quality of response of the cable at the different frequencies in the sweep signal.
Claim 23
Dependent Claim
300 words
In combination for monitoring and analyzing the quality of a cable in transmitting television signals through the cable in successive television frame times, means for providing carrier signals, means for providing control information indicative of a sweep between a particualr start frequency and a particular stop frequency in a particular time duration and at a particular repetition rate, means for converting the control information into serial digital data and for providing first and second pass signals representing in time separation the passage of the television signals through the cable in the successive television frame times, means for producing a sweep signal upon the production of the second pass signal and in accordance with the control information, means for combining the carrier signals with the digital data in serial form and with the pass signals and the sweep signals for introducing such combined signals into the television cable, means for receiving the combined signals passing through the television cable, means for demodulating the received signals to recover the digital data in serial form and the pass signals, means for processing the recovered serial digital data to provide a parity and sum check, means responsive to the parity and sum check and the first pass signal for passing the television signals in the cable in the television frame time between the pass signals, means responsive to the parity and sum check and the second pass signal for passing the television and sweep signals in the frame after each such second pass signal, and mean responsive to the operation of the last two mentioned means for comparing the signals from such last two mentioned means to recover the sweep signals in the cable for obtaining an indication of the quality of response of the cable at the different frequencies in the sweep signal.
Claim 24
Dependent Claim
68 words
The combination set forth in claim 19 wherein means responsive to the first pass signal provides for the storage of the representations of the television signals in the cable in the television frame times between the passage of the first and second pass signals and the comparing means compares the stored signals from the storing means and the signals provided in the cable after the second pass signal.
Claim 25
Dependent Claim
64 words
The combination set forth in claim 19 wherein means are provided for storing representations of the sweep signals in the cable on a weighted basis in a number of successive frames and wherein the comparing means is responsive to the sweep representations of the signals stored on the weighted basis to eliminate the effects of noise in the signals provided by the comparing means.
Claim 26
Dependent Claim
60 words
The combination set forth in claim 21 wherein means are included for storing representations of the television signals provided from the cable in the first frame times, and means are included for introducing the stored representations of the television signals to the comparing means in synchronism with the television and sweep signals in the cable in the second frame times.
Claim 27
Dependent Claim
39 words
The combination set forth in claim 22 wherein the storing means stores the television signals in the first frame times in digital form, and the introducing means converts into an analog form the stored television signals in digital form.
Claim 28
Dependent Claim
151 words
In combination for monitoring and analyzing the quality of a cable in transmitting television signals through the cable in successive television frame times, means for providing carrier signals, means for providing control information indicative of a sweep between a particular start frequency and a particular stop frequency in a particular time duration and at a particular repetition rate, means for converting the control information into serial digital data and for providing first and second pass signals representing in time separation the passage of the television signals through the cable in the successive television frame times, means for producing a sweep signal through a particular range of frequencies upon the production of the second pass signal and in accordance with the control information, and means for combining the carrier signals, the digital data in serial form, the pass signals and the sweep signals for introducing such combined signals into the television cable.
Claim 29
Dependent Claim
151 words
In combination for monitoring and analyzing the quality of a cable in transmitting television signals through the cable in successive television frame times, means for providing carrier signals, means for providing control information indicative of a sweep between a particular start frequency and a particular stop frequency in a particular time duration and at a particular repetition rate, means for converting the control information into serial digital data and for providing first and second pass signals representing in time separation the passage of the television signals through the cable in the successive television frame times, means for producing a sweep signal through a particular range of frequencies upon the production of the second pass signal and in accordance with the control information, and means for combining the carrier signals, the digital data in serial form, the pass signals and the sweep signals for introducing such combined signals into the television cable.
Claim 30
Dependent Claim
69 words
The combination set forth in claim 24 wherein the means for producing the sweep signal includes means for producing a ramp voltage in accordance with the control information indicative of the particular start frequency, the particular stop frequency, the particular time duration and the particular repetition rate and further includes a voltage controlled oscillator for producing a frequency at each instant in accordance with the voltage in the ramp.
Claim 31
Dependent Claim
38 words
The combination set forth in claim 25 wherein means are provided for regulating the gain of the carrier signals and means are provided for preventing the production of signals at individual frequencies in the particular range of frequencies.
Claim 32
Dependent Claim
103 words
The combination set forth in claim 24, including, means for receiving the combined signals passing through the television cable, means for demodulating the received signals to recover the pass signals, means responsive to the first pass signal for storing the television signals in the frame after the first pass signal, means responsive to the second pass signal for passing the television and sweep signals in the frame after the second pass signal, and means for comparing the stored television signals and the television and sweep signals from the last mentioned means to obtain a recovered sweep signal in the particular range of frequencies.
Claim 33
Dependent Claim
36 words
The combination set forth in claim 27, including, means responsive to the recovered sweep signal for providing an indication of the quality of the signal in the cable at the different frequencies in the particular range.
Claim 34
Dependent Claim
53 words
The combination set forth in claim 27, including, gate means responsive to the second pass signal and the television signals in the frame after the first pass signals for synchronizing the introduction of such signals to the comparing means with the television and sweep signals in the frame after the second pass signal.
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) | 1990-11-30 | 1991-06-01 | 1991-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-30 | 1995-06-01 | 1995-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-30 | 1999-06-01 | 1999-12-01 | $7700.00 | Window Closed / Lapsed |