| CPC H03M 1/0631 (2013.01) [H03F 3/2173 (2013.01); H03M 1/181 (2013.01)] | 22 Claims |
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1. A transition smoothing apparatus for reducing spurious input to a system under feedback control connected to a control loop of the transition smoothing apparatus comprising:
a loop filter to integrate an error between an input signal applied to the loop filter and an output signal of the system under feedback control;
an analog-to-digital converter to digitize the integrated error every loop cycle of the control loop to provide a digitized integrated error value;
a controller to generate in a normal operation mode output values supplied to the system under feedback control in response to the digitized integrated error values and adapted in a start-up sequence to control a feedback digital-to-analog converter of the control loop according to the digitized integrated error values to supply a first control signal to the loop filter of the control loop and to control the system under feedback control to generate an independent second control signal; and
an alignment detector to detect a phase alignment between the first control signal provided by the feedback digital-to-analog converter of the control loop and the second control signal provided by the system under feedback control to control a smooth transition into a closed loop operation of the control loop in the normal operation mode during the start-up sequence with reduced spurious input to the system under feedback control.
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