Pulse or digital communications – Bandwidth reduction or expansion
Reexamination Certificate
2007-09-18
2007-09-18
Payne, David C. (Department: 2611)
Pulse or digital communications
Bandwidth reduction or expansion
C375S146000, C375S147000
Reexamination Certificate
active
10730387
ABSTRACT:
An analog filter (10) having a bandwidth tracking circuit includes an analog filter element (14) and a digital tracking loop (22). The digital tracking loop (22) compares a magnitude difference to a predetermined threshold to generate an error signal. The magnitude difference is determined during a closed loop bandwidth calibration by subtracting a first magnitude of an analog input signal over a predetermined frequency range to a second magnitude of the analog input signal over the predetermined frequency range located near the bandwidth frequency. Use of the digital tracking loop (22) provides a digital approach for achieving bandwidth tracking of an analog filter without the need for achieving any manufacturing process matching between the analog filter and the tracking circuit itself. The analog filter element (14) may be either a lowpass, highpass, bandpass, active or passive filter element.
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Guimaraes Homero Luz
Rahman Mahibur
Flores Leon
Freescale Semiconductor Inc.
Hill Daniel D.
Payne David C.
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