Abstract: Provided is a filter used for an equalizer, the filter including: a first low-pass filter unit receives an input signal and performs low frequency band filtering on the input signal; and an equalization unit that receives an output signal from the first low-pass filter unit. The equalization unit may comprise a plurality of serially connected biquad low-pass filter units, and may control a value of a capacitor that is used to control a group delay value that is generated during equalization. Thus, the filter can compensate for group delay without including a separate all pass filter, thereby reducing surface area and power consumption.

Abstract: Provided is a filter used for an equalizer, the filter including: a first low-pass filter unit receives an input signal and performs low frequency band filtering on the input signal; and an equalization unit that receives an output signal from the first low-pass filter unit. The equalization unit may comprise a plurality of serially connected biquad low-pass filter units, and may control a value of a capacitor that is used to control a group delay value that is generated during equalization. Thus, the filter can compensate for group delay without including a separate all pass filter, thereby reducing surface area and power consumption.

Abstract: An equalizer, group delay compensation circuit for the equalizer and method of compensating for group delay may improve group delay characteristics in the equalizer. The equalizer circuit may include a first low pass filter configured to filter a received input signal to output a filtered input signal, and a gain control circuit connected to an output terminal of the first low pass filter, and configured to modulate a gain of a transfer function for the equalizer. The equalizer may include a group delay compensation circuit connected to the output terminal of the first low pass filter and configured to compensate for a group delay of the input signal, and a second low pass filter connected to the output terminal of the first low pass filter.

Abstract: Provided are a frequency synthesizer and a frequency synthesizing method. The frequency synthesizer includes a ring oscillator, duty buffers, half adders, and a switch. The ring oscillator receives a pair of input signals and generates a pair of oscillating signals. The duty buffers receive the pair of oscillating signals of the ring oscillator and generates output signals with predetermined duty cycles. The half adders receive output signals of the duty buffers and generate an output signal as a result of an Exclusive-OR operation on the output signals of the duty buffers and an output signal as a result of an AND operation on the output signals of the duty buffers. The switch selects one of the oscillating signals of the ring oscillator, the output signals as results of the Exclusive-OR operation, and the output signals as results of the AND operation.

Abstract: Provided are a frequency synthesizer and a frequency synthesizing method. The frequency synthesizer includes a ring oscillator, duty buffers, half adders, and a switch. The ring oscillator receives a pair of input signals and generates a pair of oscillating signals. The duty buffers receive the pair of oscillating signals of the ring oscillator and generates output signals with predetermined duty cycles. The half adders receive output signals of the duty buffers and generate an output signal as a result of an Exclusive-OR operation on the output signals of the duty buffers and an output signal as a result of an AND operation on the output signals of the duty buffers. The switch selects one of the oscillating signals of the ring oscillator, the output signals as results of the Exclusive-OR operation, and the output signals as results of the AND operation.