Method and apparatus for characterizing a radio transmitter
First Claim
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1. Apparatus for determining transient characteristics of a radio transmitter that transmits a transient signal, comprising:
- means for receiving the transient signal transmitted by the transmitter;
means for measuring the signal phase of the transient signal with respect to a predetermined frequency; and
means for analyzing the signal phase of the transient signal to determine transient characteristics of the radio transmitter.
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Accused Products
Abstract
A method and apparatus for identifying a radio transmitter. The transient frequency or phase history of the turn-on characteristics of a transmitter is detected and digitized. The history can be analyzed by a microprocessor operating a computer program to gather transient phase information from an unknown transmitter and to classify the transmitter in accordance with a transient characteristic.
71 Citations
20 Claims
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1. Apparatus for determining transient characteristics of a radio transmitter that transmits a transient signal, comprising:
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means for receiving the transient signal transmitted by the transmitter; means for measuring the signal phase of the transient signal with respect to a predetermined frequency; and means for analyzing the signal phase of the transient signal to determine transient characteristics of the radio transmitter. - View Dependent Claims (2)
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3. Apparatus for determining transient characteristics of a radio transmitter than transmits a transient signal, comprising:
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means for receiving the transient signal transmitted by the transmitter; means for measuring the difference between instantaneous frequency of the transient signal and a predetermined frequency; and means for analyzing the frequency difference to determine transient characteristics of the radio transmitter. - View Dependent Claims (4, 5)
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6. Apparatus for determining transient characteristics of a radio transmitter that transmits a transient signal during an extreme portion of a transmission, comprising:
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means for receiving the transient signal transmitted by the transmitter for a period of time including the extreme portion of the transmission; means for measuring the signal phase with respect to a predetermined frequency during the period of time; and means for analyzing the signal phase to determine transient characteristics of the radio transmitter. - View Dependent Claims (7)
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8. Apparatus for determining transient characteristics of a radio transmitter that transmits a transient signal during an extreme portion of a transmission, comprising:
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means for receiving the transient signal transmitted by the transmitter for a period of time including the extreme portion of the transmission; means for measuring the difference between instantaneous frequency of the signal and a predetermined frequency during the period of time; and means for analyzing the frequency difference to determine transient characteristics of the radio transmitter. - View Dependent Claims (9, 10)
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11. Apparatus for determining transient characteristics of a radio transmitter after it is turned on, the radio transmitter operating substantially at a predetermined frequency, comprising:
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means for receiving a transient signal transmitted by the transmitter for a predetermined period of time beginning when the radio transmitter is turned on; a frequency discriminator for measuring the phase response of the transient signal with respect to the predetermined frequency during the predetermined period of time; and means for analyzing the transient signal phase to determine turn-on transient characteristics of the radio transmitter. - View Dependent Claims (12, 13)
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14. Apparatus for determining transient characteristics of a frequency-modulated radio transmitter after it is turned on, the radio transmitter operating substantially at a predetermined carrier frequency, comprising:
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means for receiving a transient signal transmitted by the transmitter for a predetermined period of time beginning when the radio transmitter is turned on and producing a transient phase signal representative of the phase of the transient signal with respect to the predetermined carrier frequency during the predetermined period of time; means for detecting the predetermined carrier frequency in the transient signal and producing a start signal in response thereto; means for sampling the transient phase signal for the predetermined period of time in response to the start signal; storage means for storing data; and microprocessor means for analyzing the samples of the transient phase signal to determine characteristic data of the turn-on transients of the radio transmitter and for storing the characteristic data in the storage means.
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15. A method for determining transient characteristics of a radio transmitter that transmits a transient signal, comprising the steps of:
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(a) receiving the transient signal transmitted by the transmitter for a period of time; (b) passing the transient signal through a frequency discriminator; and (c) analyzing the frequency-discriminated transient signal to determine transient characteristics of the radio transmitter.
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16. A method for determining transient characteristics of a radio transmitter that transmits a transient signal, comprising the steps of:
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(a) receiving the transient signal transmitted by the transmitter for a period of time; (b) measuring a parameter of the transient signal; and (c) sampling the phase of the transient signal and digitally filtering the samples to determine transient characteristics of the radio transmitter. - View Dependent Claims (17)
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18. Apparatus for determining transient characteristics of a frequency-modulated radio transmitter that transmits a transient signal after it is turned on, the radio transmitter operating substantially at a predetermined carrier frequency, the apparatus comprising:
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means for receiving the transient signal transmitted by the transmitter for a period of time beginning when the radio transmitter is turned on and producing a signal representative of the difference between instantaneous frequency of the signal and a predetermined frequency during the period of time; means for detecting the frequency difference represented by the frequency difference signal and producing a start signal in response thereto; means for sampling the frequency difference signal in response to the start signal; storage means for storing the parametric signal samples; and microprocessor means for analyzing the frequency difference signal samples to determine characteristic data of the turn-on transients of the radio transmitter and for storing the characteristic data in the storage means. - View Dependent Claims (19, 20)
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Specification