Abstract: A variable frequency signal synthesizer includes a phase locked loop including a time-to-digital converter configured to detect differences in phase and frequency between a reference signal and a feedback clock signal and output error signals corresponding to the detected differences, a digital loop filter, a digitally controlled oscillator, and a first frequency divider configured to divide output signals of the digitally controlled oscillator at a predetermined frequency division ratio, a feedback clock generation unit configured to generate sign signals and a phase-modulated feedback clock signal, and a frequency slope tracker configured to generate a frequency control signal by accumulating differences in the error signals according to signs corresponding to the sign signals. The digitally controlled oscillator receives the frequency control signal to supply an output variable frequency signal.

Abstract: A variable frequency signal synthesizer includes a phase locked loop including a time-to-digital converter configured to detect differences in phase and frequency between a reference signal and a feedback clock signal and output error signals corresponding to the detected differences, a digital loop filter, a digitally controlled oscillator, and a first frequency divider configured to divide output signals of the digitally controlled oscillator at a predetermined frequency division ratio, a feedback clock generation unit configured to generate sign signals and a phase-modulated feedback clock signal, and a frequency slope tracker configured to generate a frequency control signal by accumulating differences in the error signals according to signs corresponding to the sign signals. The digitally controlled oscillator receives the frequency control signal to supply an output variable frequency signal.

Abstract: A reverse condition sensing mechanism incorporating in an ice making apparatus for use in a refrigerator includes a movable lever mounted on an output shaft to be rotated therewith and a fixing plate vertically mounted on a periphery surface of the output shaft. The movable lever has a shaft fixing portion fixed into the output shaft for rotating an ice tray, a rotating portion extending from the shaft fixing portion and vertically projected therefrom, and a contacting conductor mounted on a surface of the rotating portion. The fixing plate has a horizontal contact for sensing a horizontal condition of the ice tray and a reverse contact for sensing a reverse condition of the ice tray, the contacts being at intervals of a predetermined distance. The horizontal and the reverse conditions are sensed depending on the contacts being electrically contacted with the contacting conductor of the movable lever.

Abstract: An ice removing mechanism includes an ice tray having a fixing projection at one end thereof and a sliding projection at the other end thereof, a rotating guide plate having a fixing groove at one side thereof to guide the fixing projection of the ice tray inserted thereinto and a connecting shaft rotatably connected to an output shaft of a motor at the other side thereof, a fixing guide plate having a guide groove concentrically disposed to a center thereof, a twisting member disposed between the guide plates, and a movable stopper for preventing the ice tray from rocking from side to side. When the rotating guide plate is rotated, the sliding projection of the ice tray is rotated to slide along the sliding groove of the fixing guide plate, thereby pressing a bottom surface of the rotated ice tray. As a result, the ice cubes are effectively removed from the ice tray.