| 摘要 |
<p>A method for tuning a filter to a desired frequency using successive approximation. Elements of the filter are selected according to a control code used to vary the filter's oscillation frequency. The control code is set to the middle of the control code range and resulting oscillation frequency is compared to the desired frequency. If the control code needs to be increased, the control code is set to ¾ of the control code range. If the control code needs to be decreased, the control code is set to ¼ of the control code range. The method continues using successive approximation to determine the value of each bit of the control code. Thus, successive approximation is used to converge on the value of the control code that produces an oscillation frequency of the filter that is closest to the desired frequency (with a maximum error of 1 least significant bit).</p> |
