Variable rate modulator
First Claim
1. A signal processing system for converting a variable frequency input signal to an interpolated signal at a fixed sampling frequency, comprising:
- a recipient clock providing a recipient clock signal at a recipient clock frequency;
a numerically controlled oscillator responsive to a frequency control signal representing baud rate of the variable frequency input signal and the recipient clock signal for providing a second clock signal at a fixed second clock frequency representing the baud rate of said variable frequency input signal, and a phase offset signal representing an offset in phase between the recipient clock signal and the second clock signal, and an interpolator that offsets a pair of variable frequency input signals in accordance with the phase offset signal to provide the interpolated signal at the fixed sampling frequency.
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Accused Products
Abstract
Digital data signals at a variable input frequency are converted by a numerically controlled oscillator and an interpolator to a signal at a fixed output sampling frequency. The conversion of the variable input frequency to the fixed output sampling frequency may be by a factor other than an integer. The interpolated digital data signals at the fixed output sampling frequency are then modulated into a pair of trigonometric signals at a programmable carrier frequency, one signal having a cosine function and the other signal having a sine function. The modulated signals at the fixed output sampling frequency are then combined to create a modulated signal at a carrier frequency determined by the frequency of the sine and cosine signals. The modulated signal is sampled at the fixed output sampling frequency and converted to a corresponding analog signal using a digital-to-analog converter.
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Citations
9 Claims
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1. A signal processing system for converting a variable frequency input signal to an interpolated signal at a fixed sampling frequency, comprising:
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a recipient clock providing a recipient clock signal at a recipient clock frequency;
a numerically controlled oscillator responsive to a frequency control signal representing baud rate of the variable frequency input signal and the recipient clock signal for providing a second clock signal at a fixed second clock frequency representing the baud rate of said variable frequency input signal, and a phase offset signal representing an offset in phase between the recipient clock signal and the second clock signal, and an interpolator that offsets a pair of variable frequency input signals in accordance with the phase offset signal to provide the interpolated signal at the fixed sampling frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification
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- Resources
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Current AssigneeAvago Technologies International Sales Pte Limited (Broadcom, Inc.)
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Original AssigneeBroadcom Corporation (Broadcom, Inc.)
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InventorsLaskowski, Joseph J., Samueli, Henry
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Primary Examiner(s)Bayard, Emmanuel
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Application NumberUS10/272,759Publication NumberTime in Patent Office446 DaysField of Search375/306, 375/298, 375/307, 375/371, 375/375, 327/164, 327/165, 327/172, 327/178, 327/295, 327/296, 708/290, 708/251, 708/313, 708/303, 708/847, 331/18, 331/46, 331/47, 331/50US Class Current375/371CPC Class CodesH04L 27/362 Modulation using more than ...
