Compensation scheme for reducing delay in a digital impedance matching circuit to improve return loss
AssigneeTexas Instruments Incorporated
InventorsWing K. Chan, Joseph T. Nabicht
Life of this patent
Estimating the term…
Abstract
A simple, power efficient and inexpensive digital compensation scheme for reducing delay in a digital impedance matching circuit to improve return loss. The scheme employs a digital filter to compensate for the absolute sampling and digital delays associated with a digital impedance matching circuit. The digital filter is based on the low-pass function of a DAC response, and can easily be modified to correct for not only the DAC response delay, but also other delays in the digital impedance matching circuit. The digital filter is very simple to implement and can add or subtract delays from the overall system.
Claims21
A digital impedance matching circuit delay compensation system comprising:
- a low-order low pass filter cascaded with an inverse DAC filter, wherein each filter is characterized by a respective transfer function having selectable coefficients such that the delay compensation system operates to reduce delays associated with a digital impedance matching circuit to improve return loss.
A phase delay compensation system comprising:
- filtering means for digitally passing a low frequency signal;
- and
- an inverse DAC filter configured to process the filtered low frequency signal, wherein the delay compensation system is characterized by a plurality of transfer functions having selectable coefficients such that the delay compensation system operates to reduce static delays associated with a digital impedance matching circuit to improve return loss.
A method of compensating a digital impedance matching circuit to improve return loss comprising the steps of:
- providing a phase delay compensation system having means for digitally filtering a low frequency signal and an inverse DAC filter configured to process the filtered low frequency signal;
- placing the phase delay compensation system into a desired digital impedance matching circuit;
- and
- setting transfer function coefficients associated with the digital filtering means and the inverse DAC filter such that the delay compensation system operates to reduce static delays associated with the digital impedance matching circuit to improve return loss.
Dependencies are inferred from the claim text.