Patent US4093914A successfully refreshed from Google Patents.
US4093914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring parameters of a crystal filter
Assignee: Ericsson Inc
•
Filing: 1977-04-06
•
Granted: 1978-06-06
•
Expires: 1997-04-06
Abstract
Abstract Dual resonator crystal filters have an input electrode, a common electrode, and an output electrode which provide two resonators coupled together. Mathematical formulas were derived to determine the resonator frequencies, the synchronous peak separation frequency, and the normalized center frequency. These formulas use selected frequencies or parameters which can be easily measured by applying a variable band of frequencies to the input electrode of a dual crystal filter. Measurements are made of the frequencies at which the voltage at the common electrode is a maximum when the output electrode is connected to the common electrode by capacity and when the output electrode is connected to the common electrode by a short circuit. The measured frequencies can be used in the mathematical formulas to determine the resonator frequencies, the synchronous peak separation frequency, and the normalized center frequency. Other mathematical formulas were also derived to determine the resonator frequencies, the synchronous peak separation frequency, and the normalized center frequency. These other formulas use frequencies at which maximum and minimum voltages are measured when the output electrode is connected to the common electrode by a short circuit.
Inventors
- 👤 Harry J. Peppiatt
- 👤 Gerald E. Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:41
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H03H9/542; G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2688
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a plurality of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit and determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum; and b. applying a plurality of frequencies to said input electrode relative to said reference point while said output electrode and said common electrode are connected by a capacitor and determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum.
Claim 2
Independent Claim
139 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a plurality of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit and determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum; and b. applying a plurality of frequencies to said input electrode relative to said reference point while said output electrode and said common electrode are connected by a capacitor and determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said capacitor does not present a short circuit at said plurality of frequencies.
Claim 4
Independent Claim
136 words
A method of determining selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. connecting a variable frequency signal generator to said input electrode and to a reference point; b. connecting a voltage indicating device between said common electrode and said reference point; c. measuring the two frequencies produced by said signal generator when said voltage indicating device indicates a maximum voltage and while said output electrode is connected to said common electrode by capacity; and d. measuring the two frequencies produced by said signal generator when said voltage indicating device indicates a maximum voltage and while said output electrode is connected to said common electrode by a short circuit.
Claim 5
Independent Claim
136 words
A method of determining selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. connecting a variable frequency signal generator to said input electrode and to a reference point; b. connecting a voltage indicating device between said common electrode and said reference point; c. measuring the two frequencies produced by said signal generator when said voltage indicating device indicates a maximum voltage and while said output electrode is connected to said common electrode by capacity; and d. measuring the two frequencies produced by said signal generator when said voltage indicating device indicates a maximum voltage and while said output electrode is connected to said common electrode by a short circuit.
Claim 6
Dependent Claim
18 words
The method of claim 3 wherein said capacity does not present a short circuit at said two frequencies.
Claim 7
Independent Claim
147 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode mounted on one side of said plate, an output electrode mounted on said one side of said plate and spaced from said input electrode, and a common electrode mounted on an opposite side of said plate, said method comprising the steps of: a. connecting a source of signals, which can be swept in frequency, to said input electrode and a reference point; b. connecting a voltage measuring device to said common electrode and said reference point; c. sweeping the frequency of said source of signals; and d. measuring the frequencies at which said voltage measuring device indicates a maximum during the time said output electrode is connected to said common electrode by capacity and during the time said output electrode is connected to said common electrode by a short circuit.
Claim 8
Independent Claim
147 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode mounted on one side of said plate, an output electrode mounted on said one side of said plate and spaced from said input electrode, and a common electrode mounted on an opposite side of said plate, said method comprising the steps of: a. connecting a source of signals, which can be swept in frequency, to said input electrode and a reference point; b. connecting a voltage measuring device to said common electrode and said reference point; c. sweeping the frequency of said source of signals; and d. measuring the frequencies at which said voltage measuring device indicates a maximum during the time said output electrode is connected to said common electrode by capacity and during the time said output electrode is connected to said common electrode by a short circuit.
Claim 9
Dependent Claim
19 words
The method of claim 5 wherein said capacity does not present a short circuit at said frequencies of measurement.
Claim 10
Independent Claim
93 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a band of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit; and b. determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum and a minimum.
Claim 11
Independent Claim
93 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a band of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit; and b. determining the frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum and a minimum.
Claim 12
Independent Claim
113 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a band of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit; b. measuring the two frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum; and c. measuring the two frequencies which cause the voltage at said common electrode relative to said reference point to be a minimum.
Claim 13
Independent Claim
113 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode on said plate, a common electrode on said plate, and an output electrode on said plate, said method comprising the steps of: a. applying a band of frequencies to said input electrode relative to a reference point while said output electrode and said common electrode are connected by a short circuit; b. measuring the two frequencies which cause the voltage at said common electrode relative to said reference point to be a maximum; and c. measuring the two frequencies which cause the voltage at said common electrode relative to said reference point to be a minimum.
Claim 14
Independent Claim
128 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode mounted on one side of said plate, an output electrode mounted on said one side of said plate and spaced from said input electrode, and a common electrode mounted on an opposite side of said plate, said method comprising the steps of: a. connecting a source of signals, which can be swept in frequency, to said input electrode and a reference point; b. connecting a voltage measuring device to said common electrode and said reference point; c. short-circuiting said output electrode and said common electrode; and d. measuring the frequencies at which said voltage measuring device indicates a maximum and a minimum while said source of signals are swept in frequency.
Claim 15
Independent Claim
128 words
A method of measuring selected parameters of a crystal filter having a piezoelectric plate, an input electrode mounted on one side of said plate, an output electrode mounted on said one side of said plate and spaced from said input electrode, and a common electrode mounted on an opposite side of said plate, said method comprising the steps of: a. connecting a source of signals, which can be swept in frequency, to said input electrode and a reference point; b. connecting a voltage measuring device to said common electrode and said reference point; c. short-circuiting said output electrode and said common electrode; and d. measuring the frequencies at which said voltage measuring device indicates a maximum and a minimum while said source of signals are swept in frequency.
References Cited (Backward Citations)
US2293135A
Cited
US2944215A
Cited
US2991436A
Cited
US3445762A
Cited
US3397359A
Cited
US3963982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-05 | 1981-12-05 | 1982-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-05 | 1985-12-05 | 1986-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-05 | 1989-12-05 | 1990-06-06 | $7700.00 | Window Closed / Lapsed |