US3815035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tape speed compensation circuit
Assignee: GE Medical Systems Information Technologies Inc
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Filing: 1972-07-18
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Granted: 1974-06-04
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Expires: 1992-07-18
Abstract
Abstract A demodulator of the one shot multivibrator type includes means for altering the operative period of the one shot multivibrator so as to compensate for flutter effects associated with a frequency modulated data signal. The means includes a current source for charging a capacitor controlling the operative period of the one shot multivibrator in accordance with a signal corresponding to flutter effects to provide the desired compensation.
Inventors
- 👤 J Griffin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:20
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/04; G; G11; G11B; G11B20/00; G11B20/22; G11B20/225
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
289 words
In a demodulator for a frequency modulated signal having a data frequency component and a record speed variation induced flutter effects frequency component, improved circuitry for providing compensation for the flutter effects associated with the data signal from an analog signal having a magnitude corresponding to flutter effects, said circuitry being couplable to sources of said signals and comprising: a one shot multivibrator including an input for receiving the flutter affected frequency modulated signal, cyclical means coupled to said input and triggerable by the frequency characteristics of the frequency modulated signal into cycles having operative and inoperative periods, the durational relationship of which demodulates the frequency modulated signal and provides an output signal at the output of the one shot multivibrator, the average value of which is solely a function of the frequency characteristics of the frequency modulated signal, the relationship of said operative and inoperative periods being changed by the flutter effects, and a capacitor coupled to said cyclical means for determining the duration of one of the periods of the cyclical means by current responsive charge alteration; and a current source coupled to said capacitor for supplying a charge altering current to said capacitor, said current source having an input means for receiving said analog flutter effect signal for controlling the magnitude of the current and the rate of capacitor charge alteration in accordance with the magnitude of the analog flutter effect signal for changing the duration of one of the periods of the cyclical means to restore a desired durational relationship between the operative and inOperative periods and provide an output signal from the one shot multivibrator, the average value of which is solely a function of the data frequency component of the frequency modulated signal.
Claim 2
Dependent Claim
289 words
In a demodulator for a frequency modulated signal having a data frequency component and a record speed variation induced flutter effects frequency component, improved circuitry for providing compensation for the flutter effects associated with the data signal from an analog signal having a magnitude corresponding to flutter effects, said circuitry being couplable to sources of said signals and comprising: a one shot multivibrator including an input for receiving the flutter affected frequency modulated signal, cyclical means coupled to said input and triggerable by the frequency characteristics of the frequency modulated signal into cycles having operative and inoperative periods, the durational relationship of which demodulates the frequency modulated signal and provides an output signal at the output of the one shot multivibrator, the average value of which is solely a function of the frequency characteristics of the frequency modulated signal, the relationship of said operative and inoperative periods being changed by the flutter effects, and a capacitor coupled to said cyclical means for determining the duration of one of the periods of the cyclical means by current responsive charge alteration; and a current source coupled to said capacitor for supplying a charge altering current to said capacitor, said current source having an input means for receiving said analog flutter effect signal for controlling the magnitude of the current and the rate of capacitor charge alteration in accordance with the magnitude of the analog flutter effect signal for changing the duration of one of the periods of the cyclical means to restore a desired durational relationship between the operative and inOperative periods and provide an output signal from the one shot multivibrator, the average value of which is solely a function of the data frequency component of the frequency modulated signal.
Claim 3
Dependent Claim
88 words
The circuitry according to claim 1 wherein said flutter effect signal is a voltage signal and wherein said current source has a flow path including said capacitor and a resistive means, said resistive means having one end coupled to said current source input means for receiving said flutter effect voltage signal and the other end coupled to means for providing a fixed voltage at said other end so that the current in said path is determined by the application of said flutter effect voltage to said resistive means.
Claim 4
Dependent Claim
143 words
The circuitry according to claim 2 wherein said flutter effect voltage signal includes a bias level component and a component related to flutter effect through a voltage scale constant and wherein said circuitry includes a first voltage adjustment means in said current source input means for establishing the voltage scale constant of the flutter effect component at a level equal to one half the bias level component and a second voltage adjustment means in said current source input means for establishing a relationship between the fixed voltage applied to the resistive means and the bias level component such that the former is one half the latter, the adjustments provided by said first and second voltage adjustment means changing the duration of one of the periods of the one shot multivibrator responsive to the flutter effect voltage signal to completely compensate for flutter effects.
Claim 5
Dependent Claim
45 words
The circuitry according to claim 2 wherein said means for providing a fixed voltage to the other end of said resistive means includes transistor means having a power circuit connected in said current path and a control circuit connected to a source of fixed voltage.
Claim 6
Dependent Claim
33 words
The circuitry according to claim 4 wherein said transistor means comprises a transistor having its base terminal connected to said source of fixed voltage and having its emitter-collector circuit in said current path.
Claim 7
Dependent Claim
21 words
The circuitry according to claim 4 wherein said source of fixed voltage comprises a voltage divider connected across a voltage supply.
Claim 8
Dependent Claim
14 words
The circuitry according to claim 2 wherein said resistive means is of variable resistance.
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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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |