US3582837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal filter utilizing frequency-dependent variation of input impedance of one-port transducer
Assignee: Zenith Electronics LLC
•
Filing: 1967-11-08
•
Granted: 1971-06-01
•
Expires: 1987-11-08
Abstract
Abstract A body of piezoelectric material propagates acoustic surface waves. A frequency-selective transducer is coupled to a surface of the body to interact with the surface waves. The transducer has a pair of terminals and in operation exhibits at those terminals an impedance that has a significant resistive component to signals of a predetermined frequency but which has a relatively insignificant resistive component to signals of frequencies within a desired operating range but differing from that predetermined frequency. Input signals are fed to the transducer while output signals are derived therefrom. The system constitutes a filter which need have but a single transducer element coupled to the acoustic waves.
Inventors
- 👤 Adrian J Devries
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:38
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/64
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
107 words
A signal translation system comprising: a body of piezoelectric material propagative of acoustic waves; a frequency-selective transducer coupled to a surface of said body to interact with acoustic waves having frequencies within a particular range, said transducer having but a pair of terminals which in operation exhibit an impedance that has a significant resistive component to signals of a predetermined frequency within said range but has a relatively insignificant resistive component to signals within said range and differing from said predetermined frequency; input transducer; coupled to said terminals for feeding signals to said transducer; and output means coupled to said terminals for deriving signals from said transducer.
Claim 2
Dependent Claim
107 words
A signal translation system comprising: a body of piezoelectric material propagative of acoustic waves; a frequency-selective transducer coupled to a surface of said body to interact with acoustic waves having frequencies within a particular range, said transducer having but a pair of terminals which in operation exhibit an impedance that has a significant resistive component to signals of a predetermined frequency within said range but has a relatively insignificant resistive component to signals within said range and differing from said predetermined frequency; input transducer; coupled to said terminals for feeding signals to said transducer; and output means coupled to said terminals for deriving signals from said transducer.
Claim 3
Dependent Claim
54 words
A system as defined in claim 1 in which said transducer is an electrode array composed of interleaved combs of conductive elements with the center-to-center spacing between said elements being effectively one-half the length of the acoustic surface waves at said predetermined frequency, said terminals being coupled individually to respective ones of said combs.
Claim 4
Dependent Claim
34 words
A system as defined in claim 1 in which said input means includes an amplifier producing two signals of opposite phase and of respective amplitudes effecting balance between said signals at said predetermined frequency.
Claim 5
Dependent Claim
17 words
A system as defined in claim 1 in which said input means includes a balance push-pull amplifier.
Claim 6
Dependent Claim
24 words
A system as defined in claim 1 in which said input means includes means for converting unbalanced input signals to signals of balanced character.
Claim 7
Dependent Claim
116 words
A system as defined in claim 1 in which said system is arranged to include a four-armed bridge with said transducer constituting a fIrst arm of said bridge, a capacitive reactance element constituting a second arm of said bridge coupled at one end of said first arm, and a pair of impedance elements individually constituting respective third and fourth arms of said bridge and coupled in series between the other ends of said first and second arms, said input means being coupled to said third and fourth arms of said bridge and said output means being coupled between said one end of said first and second arms and the junction of said third and fourth arms.
Claim 8
Dependent Claim
29 words
A system as defined in claim 6 in which said second arm exhibits an impedance simulating the impedance exhibited by said transducer at frequencies other than said predetermined frequency.
Claim 9
Dependent Claim
84 words
A system as defined in claim 7 in which said capacitive-reactive element comprises: a frequency-selective second transducer coupled to a body of piezoelectric material propagative of acoustic surface waves to interact with the acoustic surface waves therein, said second transducer having but a pair of terminals across which in operation is exhibited an impedance having a significant resistive component to signals of a selected frequency different from said predetermined frequency and which becomes essentially capacitive to signals of frequencies departing from said selected frequency.
Claim 10
Dependent Claim
21 words
A system as defined in claim 8 in which the clamped capacitances of said first and second transducers are the same.
Claim 11
Dependent Claim
20 words
A system as defined in claim 6 in which said impedance elements of said third and fourth arms are inductive.
Claim 12
Dependent Claim
43 words
A system as defined in claim 6 in which, for signals departing in frequency from said predetermined frequency by a specific amount, the impedance of said capacitive reactance element in said second arm is substantially equal to the impedance exhibited across said terminals.
Claim 13
Dependent Claim
45 words
A system as defined in claim 1 in which said transducer interacts with acoustic waves propagating generally in a given direction along a surface of said body and in which said body includes means located in the path of and attenuative of said acoustic waves.
Claim 14
Dependent Claim
46 words
A system as defined in claim 1 in which said transducer interacts with acoustic waves propagating generally in a given direction along a surface of said body and in which an end surface of said body oriented generally transverse to said direction is of irregular contour.
Claim 15
Dependent Claim
113 words
A signal translation system comprises: a body of piezoelectric material propagative of acoustic waves; a first frequency-selective transducer coupled to a first surface portion of said body to interact with a first set of acoustic surface waves on said body; a second frequency-selective transducer coupled to a second surface portion of said body to interact with a second set of acoustic surface waves on said body; means for applying signals, in push-pull relation relative to a plane of reference potential, across said first and second transducers in series combination; and means for deriving signals from a point in said series combination intermediate said first and second transducers and said plane of reference potential.
Claim 16
Dependent Claim
113 words
A signal translation system comprises: a body of piezoelectric material propagative of acoustic waves; a first frequency-selective transducer coupled to a first surface portion of said body to interact with a first set of acoustic surface waves on said body; a second frequency-selective transducer coupled to a second surface portion of said body to interact with a second set of acoustic surface waves on said body; means for applying signals, in push-pull relation relative to a plane of reference potential, across said first and second transducers in series combination; and means for deriving signals from a point in said series combination intermediate said first and second transducers and said plane of reference potential.
References Cited (Backward Citations)
US2001387A
Cited
US3070761A
Cited
US3300739A
Cited
US3401360A
Cited
US3289114A
Cited
US3360749A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |