US3908165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field strength meter
Assignee: Meritor Inc
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Filing: 1974-06-10
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Granted: 1975-09-23
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Expires: 1994-06-10
Abstract
Abstract A signal strength meter indicates signal level directly in dBmV. The signal under test is attenuated to a level which centers a meter indicator, and the attenuator movement is translated into numerical direct reading information of signal level. Push button switches select a channel for testing, and each switch incorporates gain compensation for the frequency of the signal to be tested. Within each channel the operator can select between audio and video carrier frequency.
Inventors
- 👤 Jack D Cauldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:28
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/0007; G01R29/00; G01R29/08; G01R29/0864; G01R29/0871
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
176 words
A signal level instrument for indicating the level of an R.F. signal present in a circuit over a relatively wide range of frequency, said instrument comprising an input connection adapted to be connected to a signal source to be tested, selectively operable attenuator means connected to receive a signal from said input connection and to attenuate the received signal to a predetermined level, a channel selector adjustable to the frequency band of a particular signal being received at said input connection, said channel selector including a variable gain compensation control selected by said channel selector to provide a gain compensation related to differences in gain of the instrument circuitry at different frequencies, an indicator driven at a level corresponding to the output of said attenuator means and also compensated by a signal from said variable gain control to indicate when said attenuator means has attenuated the received signal to the predetermined level, and readout means operated by said attenuator means to indicate the amount of attenuation introduced thereby as a direct reading of incoming signal level.
Claim 2
Dependent Claim
176 words
A signal level instrument for indicating the level of an R.F. signal present in a circuit over a relatively wide range of frequency, said instrument comprising an input connection adapted to be connected to a signal source to be tested, selectively operable attenuator means connected to receive a signal from said input connection and to attenuate the received signal to a predetermined level, a channel selector adjustable to the frequency band of a particular signal being received at said input connection, said channel selector including a variable gain compensation control selected by said channel selector to provide a gain compensation related to differences in gain of the instrument circuitry at different frequencies, an indicator driven at a level corresponding to the output of said attenuator means and also compensated by a signal from said variable gain control to indicate when said attenuator means has attenuated the received signal to the predetermined level, and readout means operated by said attenuator means to indicate the amount of attenuation introduced thereby as a direct reading of incoming signal level.
Claim 3
Dependent Claim
45 words
An instrument as defined in claim 1, wherein said selector means comprises individual switches and compensation networks for each frequency band on which a test signal may be present within the range of the instrument whereby selection of a desired frequency automatically introduces appropriate compensation.
Claim 4
Dependent Claim
55 words
An instrument as defined in claim 1, including a variable frequency oscillator, a mixer receiving the outputs of said oscillator and said attenuator means and producing a reference output at a predetermined frequency and level, said channel selector controlling said oscillator to vary its frequency according to the selected frequency of the signal under test.
Claim 5
Dependent Claim
53 words
An instrument as defined in claim 3, wherein the signal under test includes video and audio portions within the selected frequency band, and switch means cooperating with said channel selector and said oscillator to shift the oscillator frequency within a selected band sufficiently to permit separate portions of the signal to be tested.
Claim 6
Dependent Claim
53 words
An instrument as defined in claim 1, said attenuator means including a pair of individually controlled step switches and corresponding separate actuators for said switches, said readout means including separate indicators movable by each of said actuators and coacting to display the amount of attenuation introduced digitally in + or - db MV.
Claim 7
Dependent Claim
163 words
An instrument for measuring and directly indicating signal level of selected R.F. signals within a wide frequency range, such as in a cable television system, comprising an input connector for receiving a signal under test, manually adjustable attenuator means connected to said input connector and including readout means for indicating the amount of attenuation introduced, a mixer receiving the attenuated signal, a variable frequency oscillator having an output to said mixer, channel selector means manually operable to vary the frequency of said oscillator according to the carrier frequency of the signal under test causing said mixer to produce a reference signal at a predetermined frequency and varying in level with adjustment of said attenuator means, a meter, and a meter driver circuit having an output to said meter and an input varying in accordance with the level of said reference signal whereby driving said meter to a predetermined condition causes said readout means to indicate directly the level of the signal under test.
Claim 8
Dependent Claim
163 words
An instrument for measuring and directly indicating signal level of selected R.F. signals within a wide frequency range, such as in a cable television system, comprising an input connector for receiving a signal under test, manually adjustable attenuator means connected to said input connector and including readout means for indicating the amount of attenuation introduced, a mixer receiving the attenuated signal, a variable frequency oscillator having an output to said mixer, channel selector means manually operable to vary the frequency of said oscillator according to the carrier frequency of the signal under test causing said mixer to produce a reference signal at a predetermined frequency and varying in level with adjustment of said attenuator means, a meter, and a meter driver circuit having an output to said meter and an input varying in accordance with the level of said reference signal whereby driving said meter to a predetermined condition causes said readout means to indicate directly the level of the signal under test.
Claim 9
Dependent Claim
30 words
An instrument as defined in claim 6, including a selectively adjustable gain compensation circuit controlled by said channel selector and connected to supply a gain compensation to said meter drive.
Claim 10
Dependent Claim
49 words
An instrument as defined in claim 7, said channel selector means including a separate switch for each channel, and said gain compensation circuit including individual compensation components for each channel connected to a corresponding selector switch whereby selection of a channel automatically introduces gain compensation appropriate to that channel.
Claim 11
Dependent Claim
46 words
An instrument as defined in claim 6, inCluding a manually operable selector switch means connected to said channel selector means and operable to shift the frequency of said oscillator between different carrier frequencies within a band of frequencies selected by operation of said channel selector means.
Claim 12
Dependent Claim
44 words
An instrument as defined in claim 9, wherein said oscillator is a voltage controlled oscillator, said channel selector means provides predetermined control voltages to said oscillator corresponding to different frequency bands, and said selector switch means provides a further change in the control voltage.
Claim 13
Dependent Claim
128 words
An instrument as defined in claim 6, wherein said mixer operates to provide selectively reference signals at different frequencies, filter circuits receiving respective ones of said reference signals, switching means operated from said channel selector means and connected to activate the appropriate filter circuit according to the selected frequency of the signal under test, a second mixer receiving the output of said filter circuits and providing a reduced frequency reference output to said meter driver, selectively operable fixed frequency oscillators connected to said second mixer, and said switching means having actuating connections to said fixed frequency oscillators to actuate that oscillator corresponding to the selected filter circuit whereby the output of said second mixer is the same predetermined frequency with any one of the filter circuits in use.
Claim 14
Independent Claim
110 words
The method of testing the level of R.F. signals present over a wide range of frequency in a transmission system, comprising the steps of attenuating the signal under test, producing from the attenuated signal a reference signal at a predetermined reference level, compensating the reference signal for frequency, driving a signal level responsive indicator to a predetermined position with the compensated reference signal by adjusting the amount of attenuation until the attenuated signal is at a predetermined level corresponding to the predetermined indicator position, and producing from the attenuating step a direct reading of the amount of attenuation introduced as a measure of the level of the signal under test.
Claim 15
Independent Claim
110 words
The method of testing the level of R.F. signals present over a wide range of frequency in a transmission system, comprising the steps of attenuating the signal under test, producing from the attenuated signal a reference signal at a predetermined reference level, compensating the reference signal for frequency, driving a signal level responsive indicator to a predetermined position with the compensated reference signal by adjusting the amount of attenuation until the attenuated signal is at a predetermined level corresponding to the predetermined indicator position, and producing from the attenuating step a direct reading of the amount of attenuation introduced as a measure of the level of the signal under test.
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |