US3878374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Densitometer
Assignee: TDK Micronas GmbH
•
Filing: 1973-12-10
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Granted: 1975-04-15
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Expires: 1993-12-10
Abstract
Abstract A vibration densitometer including a closed loop electromechanical oscillator for vibrating a fluid immersible vane. A digital output directly proportional to density is achieved through a unique digital squarer. The densitometer is an all digital system. In the loop, a tracking filter is provided. Separate search and track automatic gain control feedbacks are provided. A threshold detector controls clamps and a gate to cause the voltage controlled oscillator of a first phase lock loop to search or track the vane resonant frequency. The threshold detector also effects the search feedback. A phase adjustment circuit and a second phase lock loop are employed to impress a sine wave voltage component on the vane driver of a phase which creates maximum efficiency.
Inventors
- 👤 Gerald Lance Schlatter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:51
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; G; G01; G01N; G01N9/00; G01N9/002; G01N2009/008
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
708 words
A digital vibration densitometer comprising: a probe including a housing, a vane, electrical means having an input lead, and a detector having an output lead, said vane being mounted on said housing, said electrical means being mounted on said housing and being responsive to a feedback signal impressed upon said input lead thereof to vibrate said vane, said detector being mounted on said housing in a position to receive vibrations of said vane, said detector producing an output signal on said output lead thereof responsive to receipt of vibrations from said vane, said output signal having an A.C. component of a frequency equal to the vibrational frequency of said vane; first means having input and output leads, said first means input lead being connected from said detector output lead to produce a periodic signal on said first means output lead of a fundamental frequency equal to said vibrational frequency; second means having input and output leads, said second means input lead being connected from said first means output lead to said electrical means input lead to impress said feedback signal thereon, said feedback signal providing positive feedback to cause said probe and said first and second means to act as a closed loop electromechanical oscillator, at least one of said first and second means including an amplifier, at least one of said first and second means being constructed to provide gain for said loop to overcome damping of said loop including damping of said vane to an extent such that said electromechanical oscillator oscillates continuously and said vane vibrates continuously; a termainal junction; third means having input and output leads, said third means input and output leads being connected from said first means output lead to said terminal junction, respectively, to impress a square wave on said terminal junction having a pulse repetition frequency (PRF) directly proportional to said fundamental frequency and a markto-space ratio of unity; first and second NAND gates, each of said NAND gates having first and second input leads and an output lead; a burst oscillator having a constant PRF large in comparison to that of said square wave; an inverter having an input lead connected from said terminal junction, and an output lead connected to said second gate first input lead, said first gate first lead being connected from said terminal junction, said burst oscillator having an output lead connected to the second lead of each of said first and second gates; a divider having at least a first input lead, and a plurality of outputs leads, said divider acting as a counter and having a storage register with a constant count entered therein during alternate half periods of said square wave, pulses counted by said divider being supplied over said first input lead thereof thereto, said divider first input lead being connected from one of said gate outpuT leads; a first rate multiplier having a plurality of setting input leads connected from respective bits in said divider register, said first rate multiplier having a serial pulse input lead connected from the other of said gate output leads and a serial pulse output lead; a manually adjustable switch matrix having a plurality of output leads; a second rate multiplier having a plurality of setting input leads connected respectively from said matrix output leads, a serial pulse input lead connected from said first rate multiplier serial pulse output lead, and an output lead, said second rate multiplier producing a number of serial pulses on the output lead thereof during said alternate half periods of said square wave directly proportional to AT2 where A is the constant introduced by adjustment of said switch matrix and T is the period of said square wave, the number of pulses produced serially by said first rate multiplier on the said serial pulse output lead thereof being directly proportional to T2; an off-set digital computer having at least a first input lead connected from said second rate multiplier serial pulse output lead, said computer having a plurality of output leads and being adapted to produce digital output signals on said output leads thereof directly proportional to the quantity AT2 + B where B is a constant, said computer having an adjustable switch matrix, the adjustment of which varies B.
Claim 2
Dependent Claim
708 words
A digital vibration densitometer comprising: a probe including a housing, a vane, electrical means having an input lead, and a detector having an output lead, said vane being mounted on said housing, said electrical means being mounted on said housing and being responsive to a feedback signal impressed upon said input lead thereof to vibrate said vane, said detector being mounted on said housing in a position to receive vibrations of said vane, said detector producing an output signal on said output lead thereof responsive to receipt of vibrations from said vane, said output signal having an A.C. component of a frequency equal to the vibrational frequency of said vane; first means having input and output leads, said first means input lead being connected from said detector output lead to produce a periodic signal on said first means output lead of a fundamental frequency equal to said vibrational frequency; second means having input and output leads, said second means input lead being connected from said first means output lead to said electrical means input lead to impress said feedback signal thereon, said feedback signal providing positive feedback to cause said probe and said first and second means to act as a closed loop electromechanical oscillator, at least one of said first and second means including an amplifier, at least one of said first and second means being constructed to provide gain for said loop to overcome damping of said loop including damping of said vane to an extent such that said electromechanical oscillator oscillates continuously and said vane vibrates continuously; a termainal junction; third means having input and output leads, said third means input and output leads being connected from said first means output lead to said terminal junction, respectively, to impress a square wave on said terminal junction having a pulse repetition frequency (PRF) directly proportional to said fundamental frequency and a markto-space ratio of unity; first and second NAND gates, each of said NAND gates having first and second input leads and an output lead; a burst oscillator having a constant PRF large in comparison to that of said square wave; an inverter having an input lead connected from said terminal junction, and an output lead connected to said second gate first input lead, said first gate first lead being connected from said terminal junction, said burst oscillator having an output lead connected to the second lead of each of said first and second gates; a divider having at least a first input lead, and a plurality of outputs leads, said divider acting as a counter and having a storage register with a constant count entered therein during alternate half periods of said square wave, pulses counted by said divider being supplied over said first input lead thereof thereto, said divider first input lead being connected from one of said gate outpuT leads; a first rate multiplier having a plurality of setting input leads connected from respective bits in said divider register, said first rate multiplier having a serial pulse input lead connected from the other of said gate output leads and a serial pulse output lead; a manually adjustable switch matrix having a plurality of output leads; a second rate multiplier having a plurality of setting input leads connected respectively from said matrix output leads, a serial pulse input lead connected from said first rate multiplier serial pulse output lead, and an output lead, said second rate multiplier producing a number of serial pulses on the output lead thereof during said alternate half periods of said square wave directly proportional to AT2 where A is the constant introduced by adjustment of said switch matrix and T is the period of said square wave, the number of pulses produced serially by said first rate multiplier on the said serial pulse output lead thereof being directly proportional to T2; an off-set digital computer having at least a first input lead connected from said second rate multiplier serial pulse output lead, said computer having a plurality of output leads and being adapted to produce digital output signals on said output leads thereof directly proportional to the quantity AT2 + B where B is a constant, said computer having an adjustable switch matrix, the adjustment of which varies B.
Claim 3
Dependent Claim
17 words
The invention as defined in claim 1, wherein utilization means are connected from said computer output leads.
Claim 4
Dependent Claim
68 words
The invention as defined in claim 2, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in weight per unit volume.
Claim 5
Dependent Claim
66 words
The invention as defined in claim 2, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in specific gravity.
Claim 6
Dependent Claim
54 words
The invention as defined in claim 1, including fourth means connected from the first input lead of the one gate having the said one output lead thereof to reset said divider to zero on each leading edge of each pulse of the square wave appearing on the first input lead of said one gate.
Claim 7
Dependent Claim
21 words
The invention as defined in claim 5, wherein said computer has second and third input leads connected from said third means.
Claim 8
Dependent Claim
17 words
The invention as defined in claim 6, wherein utilization means are connected from said computer output leads.
Claim 9
Dependent Claim
68 words
The invention as defined in claim 7, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in weight per unit volume.
Claim 10
Dependent Claim
66 words
The invention as defined in claim 7, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in specific gravity.
Claim 11
Dependent Claim
17 words
The invention as defined in claim 5, wherein utilization means are connected from said computer ouTput leads.
Claim 12
Dependent Claim
68 words
The invention as defined in claim 10, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in weight per unit volume.
Claim 13
Dependent Claim
66 words
The invention as defined in claim 10, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in specific gravity.
Claim 14
Dependent Claim
21 words
The invention as defined in claim 1, wherein said computer has second and third input leads connected from said third means.
Claim 15
Dependent Claim
17 words
The invention as defined in claim 13, wherein utilization means are connected from said computer output leads.
Claim 16
Dependent Claim
68 words
The invention as defined in claim 14, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in weight per unit volume.
Claim 17
Dependent Claim
66 words
The invention as defined in claim 14, wherein said computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator PRF being of a second predetermined magnitude, said switch matrices being adjusted to cause said indicator to read directly in specific gravity.
Claim 18
Dependent Claim
469 words
A vibrational densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit having an output junction and first means to cause a periodic signal to appear at said output junction of a fundamental frequency equal to the frequency at which said structure vibrates; a terminal junction; second means connected between said junctions for impressing a square wave on said terminal junction having a period directly proportional to that of said periodic signal fundamental frequency and having a mark-to-space ratio equal to unity; first and second NAND gates, each of said NAND gates having first and second input leads and an output lead; a burst oscillator having a constant pulse repetition frequency large in comparison to that of said square wave; an inverter having an input lead connected from said terminal junction, and an output lead connected to said second gate first input lead, said first gate first input lead being connected from said terminal junction, said burst oscillator having an output lead connected to the second lead of each of said first and second gates; a divider having at least a first input lead, said divider acting as a counter and having a storage register with a constant count entered therein during alternate half periods of said square wave, said storage register having a plurality of output leads, pulses counted by said divider being supplied over said first input lead thereof, said divider first input lead being connected from one of said gate output leads; a rate multiplier having a plurality of setting input leads connected from respective divider register output leads, said rate multiplier having a serial pulse inpUt lead connected from the other of said gate output leads and a serial pulse output lead, said rate multiplier producing serial groups of serial pulses on said output lead thereof, the number of pulses in a rate multiplier group being directly proportional to T2 where T is the period of said square wave; an off-set digital computer having an input lead and a plurality of output leads; and third means having an input lead connected from said rate multiplier serial pulse output lead, and an output lead connected to said off-set computer input lead, said third means producing serial groups of serial pulses, the number of pulses in a third means group being directly proportional to AT2, where A is a constant, said off-set computer producing signals on said output leads thereof representative of a digital number of directly proportional to AT2 + B where B is a constant.
Claim 19
Dependent Claim
469 words
A vibrational densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit having an output junction and first means to cause a periodic signal to appear at said output junction of a fundamental frequency equal to the frequency at which said structure vibrates; a terminal junction; second means connected between said junctions for impressing a square wave on said terminal junction having a period directly proportional to that of said periodic signal fundamental frequency and having a mark-to-space ratio equal to unity; first and second NAND gates, each of said NAND gates having first and second input leads and an output lead; a burst oscillator having a constant pulse repetition frequency large in comparison to that of said square wave; an inverter having an input lead connected from said terminal junction, and an output lead connected to said second gate first input lead, said first gate first input lead being connected from said terminal junction, said burst oscillator having an output lead connected to the second lead of each of said first and second gates; a divider having at least a first input lead, said divider acting as a counter and having a storage register with a constant count entered therein during alternate half periods of said square wave, said storage register having a plurality of output leads, pulses counted by said divider being supplied over said first input lead thereof, said divider first input lead being connected from one of said gate output leads; a rate multiplier having a plurality of setting input leads connected from respective divider register output leads, said rate multiplier having a serial pulse inpUt lead connected from the other of said gate output leads and a serial pulse output lead, said rate multiplier producing serial groups of serial pulses on said output lead thereof, the number of pulses in a rate multiplier group being directly proportional to T2 where T is the period of said square wave; an off-set digital computer having an input lead and a plurality of output leads; and third means having an input lead connected from said rate multiplier serial pulse output lead, and an output lead connected to said off-set computer input lead, said third means producing serial groups of serial pulses, the number of pulses in a third means group being directly proportional to AT2, where A is a constant, said off-set computer producing signals on said output leads thereof representative of a digital number of directly proportional to AT2 + B where B is a constant.
Claim 20
Dependent Claim
34 words
The invention as defined in claim 17, wherein said third means includes fourth means to adjust manually the magnitude of A, said off-set computer including fifth means to adjust manually the magnitude of B.
Claim 21
Dependent Claim
18 words
The invention as defined in claim 18, wherein utilization means are connected from said off-set computer output leads.
Claim 22
Dependent Claim
78 words
The invention as defined in claim 19, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in weight per unit volume.
Claim 23
Dependent Claim
76 words
The invention as defined in claim 19, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in specific gravity.
Claim 24
Dependent Claim
54 words
The invention as defined in claim 18, including sixth means connected from the first input lead of the one gate having the said one output lead thereof to reset said divider to zero on each leading edge of said pulse of the square wave appearing on the first input lead of said one gate.
Claim 25
Dependent Claim
22 words
The invention as defined in claim 22, wherein said off-set computer has second and third input leads connected from said second means.
Claim 26
Dependent Claim
18 words
The invention as defined in claim 23, wherein utilization means are connected from said off-set computer output leads.
Claim 27
Dependent Claim
78 words
The invention as defined in claim 24, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in weight per unit volume.
Claim 28
Dependent Claim
76 words
The invention as defined in claim 24, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in specific gravity.
Claim 29
Dependent Claim
18 words
The invention as defined in Claim 22, wherein utilization means are conNected from said off-set computer output leads.
Claim 30
Dependent Claim
78 words
The invention as defined in claim 27, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in weight per unit volume.
Claim 31
Dependent Claim
76 words
The invention as defined in claim 27, wherein said off-set computer output signals are binary coded decimal signals, sais utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in specific gravity.
Claim 32
Dependent Claim
20 words
The invention as defined in claim 18, wherein said computer has second and third input leads connected from second means.
Claim 33
Dependent Claim
18 words
The invention as defined in claim 30, wherein utilization means are connected from said offset computer output leads.
Claim 34
Dependent Claim
78 words
The invention as defined in claim 31, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in weight per unit volume.
Claim 35
Dependent Claim
76 words
The invention as defined in claim 31, wherein said off-set computer output signals are binary coded decimal signals, said utilization means including a decimal indicator, the ratio of T to the vibrational period of said vane being of a first predetermined magnitude, said burst oscillator pulse repetition frequency being of a second predetermined magnitude, said fourth means and said fifth means adjusting A and B, respectively, to cause said indicator to read directly in specific gravity.
Claim 36
Dependent Claim
431 words
A vibration densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit including a tracking filter having first and second input leads and first and second output leads, said tracking filter being constructed to produce first and second output signals on said first and second output leads thereof, respectively, said first tracking filter output signal lagging said second tracking filter output signal in phase by 90*; first means connecting said loop circuit input lead to said tracking filter first input lead; second means having input and output leads connected respectively from and to said tracking filter second output lead and said tracking filter second input lead, said first means impressing a signal on said tracking filter first input lead of a frequency equal to the frequency Delta t which said structure vibrates, said second means applying a control signal to said tracking filter second input lead of a type to cause the tracking filter passband to move to a location straddling the frequency of the signal impressed upon said tracking filter first input lead; a zero crossing detector having input and output leads; a phase detector having input and output leads; a low pass filter having input and output leads, said zero crossing detector having said output and input leads thereoF connected respectively to said tracking filter first output lead and said phase detector input lead, said phase detector output lead being connected to said low pass filter input lead; an output junction; third means having an input lead connected from said low pass filter output lead, and an output lead connected to said output junction, said third means impressing a signal on said output junction of said vibrational frequency; fourth means having input and output leads connected to said output junction and to said loop circuit output lead, respectively, said fourth means exciting said probe in a manner to cause said structure to vibrate; fifth means having an input lead connected from said output junction, said fifth means having output lead means and being constructed to produce output signals on said output lead thereof directly proportional to AT2 + B where T is the reciprocal of said vibrational frequency, and A and B are constants; and utilization means having input lead means connected from said fifth means output lead means.
Claim 37
Dependent Claim
431 words
A vibration densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit including a tracking filter having first and second input leads and first and second output leads, said tracking filter being constructed to produce first and second output signals on said first and second output leads thereof, respectively, said first tracking filter output signal lagging said second tracking filter output signal in phase by 90*; first means connecting said loop circuit input lead to said tracking filter first input lead; second means having input and output leads connected respectively from and to said tracking filter second output lead and said tracking filter second input lead, said first means impressing a signal on said tracking filter first input lead of a frequency equal to the frequency Delta t which said structure vibrates, said second means applying a control signal to said tracking filter second input lead of a type to cause the tracking filter passband to move to a location straddling the frequency of the signal impressed upon said tracking filter first input lead; a zero crossing detector having input and output leads; a phase detector having input and output leads; a low pass filter having input and output leads, said zero crossing detector having said output and input leads thereoF connected respectively to said tracking filter first output lead and said phase detector input lead, said phase detector output lead being connected to said low pass filter input lead; an output junction; third means having an input lead connected from said low pass filter output lead, and an output lead connected to said output junction, said third means impressing a signal on said output junction of said vibrational frequency; fourth means having input and output leads connected to said output junction and to said loop circuit output lead, respectively, said fourth means exciting said probe in a manner to cause said structure to vibrate; fifth means having an input lead connected from said output junction, said fifth means having output lead means and being constructed to produce output signals on said output lead thereof directly proportional to AT2 + B where T is the reciprocal of said vibrational frequency, and A and B are constants; and utilization means having input lead means connected from said fifth means output lead means.
Claim 38
Dependent Claim
26 words
The invention as defined in claim 34, wherein said utilization means is an indicator for the magnitude of the signal impressed thereon and calibrated in density.
Claim 39
Dependent Claim
27 words
The invention as defined in claim 34, wherein said utilization means is an indicator for the magnitude of the signal impressed thereon and calibrated in specific gravity.
Claim 40
Dependent Claim
36 words
The invention as defined in claim 34, wherein said first means has a series connected stage including an automatic gain control (AGC) amplifier having an AGC input lead connected from said zero crossing detector output lead.
Claim 41
Dependent Claim
26 words
The invention as defined in claim 37, wherein said utilization means is an indicator for the magnitude of the signal impressed thereon and calibrated in density.
Claim 42
Dependent Claim
27 words
The invention as defined in claim 37, wherein said utilization means is an indicator for the magnitude of the signal impressed thereon and calibrated in specific gravity.
Claim 43
Dependent Claim
386 words
A vibration densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit including a first clamp having first and second input leads and an output lead; first means connected between said loop circuit input lead and said first clamp first input lead to impress a periodic signal on said first clamp first input lead of a fundamental frequency equal to the frequency of vibration of said structure; a sweep oscillator having power input and output leads; a threshold detector having input and output leads, said threshold detector producing a step signal on its output lead when the input signal magnitude on its input lead passes through a predetermined magnitude; second means having input and output leads connected to said first means and said threshold detector input lead, respectively, to supply a signal to said threshold detector on said input lead thereof of a magnitude proportional to the magnitude of the signal passing through said probe producing an output signal on its output lead of a frequency equal to said frequency of vibration; an inverter having input and output leads, said threshold detector having its output lead connected to said first clamp second input lead and to said inverter input lead; a phase lock loop including a phase detector having first and second input leads and an output lead, said first clamp output lead being connected to said phase detector first input lead, said inverter output lead being connected to said sweep oscillator power input lead; said phase lock loop having a voltage controlled oscillator with an input lead connected from an output lead of said phase detector and an output lead connected to said phase detector second input lead; thirD means connecting the output of said sweep oscillator to the input of said voltage controlled oscillator; fourth means connected from said voltage controlled oscillator output lead to said loop circuit output lead to impress a signal on said probe input lead to cause said structure to be vibrated; and utilization means connected from said fourth means.
Claim 44
Dependent Claim
386 words
A vibration densitometer comprising: an electromechanical oscillator including a probe and a loop circuit, said probe and said loop circuit each having an input lead and an output lead, said probe output lead being connected to said loop circuit input lead, said loop circuit output lead being connected to said probe input lead, said probe having a vibratable structure, said loop circuit including a first clamp having first and second input leads and an output lead; first means connected between said loop circuit input lead and said first clamp first input lead to impress a periodic signal on said first clamp first input lead of a fundamental frequency equal to the frequency of vibration of said structure; a sweep oscillator having power input and output leads; a threshold detector having input and output leads, said threshold detector producing a step signal on its output lead when the input signal magnitude on its input lead passes through a predetermined magnitude; second means having input and output leads connected to said first means and said threshold detector input lead, respectively, to supply a signal to said threshold detector on said input lead thereof of a magnitude proportional to the magnitude of the signal passing through said probe producing an output signal on its output lead of a frequency equal to said frequency of vibration; an inverter having input and output leads, said threshold detector having its output lead connected to said first clamp second input lead and to said inverter input lead; a phase lock loop including a phase detector having first and second input leads and an output lead, said first clamp output lead being connected to said phase detector first input lead, said inverter output lead being connected to said sweep oscillator power input lead; said phase lock loop having a voltage controlled oscillator with an input lead connected from an output lead of said phase detector and an output lead connected to said phase detector second input lead; thirD means connecting the output of said sweep oscillator to the input of said voltage controlled oscillator; fourth means connected from said voltage controlled oscillator output lead to said loop circuit output lead to impress a signal on said probe input lead to cause said structure to be vibrated; and utilization means connected from said fourth means.
Claim 45
Dependent Claim
112 words
The invention as defined in claim 40, including a second clamp having first and second input leads and an output lead, said second clamp first input lead being connected from said inverter output lead, an output junction, said fourth means including means connected from said voltage controlled oscillator output lead to said output junction to impress a square wave on said output junction having a fundamental frequency equal to said vibrational frequency, said second clamp second input lead being connected from said output junction, said first means including an automatic gain control (AGC) amplifier having an AGC input lead, said second clamp output lead being connected to said gain control input lead.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |