Abstract:
A multiplying digital to analog converter and pipelined analog to a digital converter having the same are provided to obtain a desired value in a first timing by making the pipeline analog digital convertor have high gain in second timing. In a multiplying digital to analog converter and pipelined analog to a digital converter having the same, a sample/hold part(110) receives an analog signal. The sample/hold part produces an analog input signal by performing the sampling and holding calculation. A stage unit(120) receives analog input signal, and the stage part outputs a digital stage output power signal consisting of 1.5 bit or 2 bit. The stage part is divided into a first stage including a multiplying digital to analog converter and a second stage(122b) not including the multiplying digital to analog converter.
Abstract:
A time-to-digital converting circuit is provided to minimize influence of peripheral noise without an analog circuit by generating digital data according to changed delay time after changing the delay time of a sensing signal according to intensity of an external stimulus. A time-to-digital converting circuit includes a delay variable unit(30), and a delay calculating and data generating unit(40). The delay variable unit(30) generates a reference signal(ref) having a fixed delay and a sensing signal(sen) having a delay variable according to an impedance value of an external signal. The delay calculating and data generating unit(40) calculates a delay difference between the reference signal(ref) and the sensing signal(sen), and generates digital data having a value corresponding to the calculated delay difference.
Abstract:
PURPOSE: A digital to analog converter for a continuous time sigma delta modulator is provided to improve performance of the converter by controlling a duty ratio of a clock signal. CONSTITUTION: An adding unit(110) adds up a continuous time analog input signal and an analog signal outputted from a digital to analog converter(140). A loop filter(120) includes at least one integrator to perform an integral operation. The integrator is comprised of an operational amplifier and a capacitor. A quantizer(130) performs the quantization operation based on the signal outputted from the loop filter and outputs the digital signal. The digital signal is comprised of one bit or plural bits. The digital to analog converter outputs the analog signal based on the digital signal outputted from the quantizer.
Abstract:
A multi-bit delta sigma modulator is provided to be applied for a multi-bit high speed operation by delaying a feedback signal as much as one clock using a delayer and a differential delayer. A multi-bit delta sigma modulator includes a first integrator(301), a second integrator(303), an analog digital converter(305), a delayer(309), and a differential delayer(311). The first integrator integrates an input signal. The second integrator receives an input of the signal feedbacked from the differential delayer, and compensates for the delayed signal component. The analog digital converter converts the integrated signal into a digital signal. The delayer delays the signal outputted from the analog digital converter. The differential delayer differentiates and delays the signal outputted from the analog digital converter.
Abstract:
PURPOSE: A dual channel analog to digital converter (ADC) is provided to sample an input signal by using a sampling clock of each channel by solving a mismatching problem. CONSTITUTION: An ADC comprises an SHA (110), an MDAC (120-130), an SHA sampling clock generator, and a flash ADC (140-160). An input end of the SHA or the MDAC constructs an X channel and a Y channel. The X channel shares an amplifier with the Y channel. The SHA sampling clock generator generates the sampling clock of the X channel and the sampling clock of the Y channel. The sampling clock of the X channel and the sampling clock of the Y channel are synchronized with a falling edge of a reference clock. A delay control circuit controls the delay time of a reference clock synchronizing with the SHA sampling clock generating the SHA sampling clock generator used in a digital correction circuit.
Abstract:
PURPOSE: A multiplier-free algorithm for estimating sample-time and a gain mismatch error in a two-channel time-interleaved analog to digital converter are provided to deduct an absolute value of an output from two ADCs using a gain mismatch error estimation algorithm. CONSTITUTION: An input signal is converted into first and second digital signals with two time-leaved analog digital converter cores in order to provide a set of two ADC outputs. At least one of the two time-leaved analog digital converter cores has a correction input. The first and second digital signals are interleaved in order to form an expression of being converted into a digital format of the input signal. An error is estimated using a code value which is determined from the first and second digital signals. The correction signal is determined from the error. The correction signal is applied one or more correction input of the two time-leaved analog digital converter cores. [Reference numerals] (AA,DD) Spectrum of a signal having a sample-time mismatch error; (BB) Size(dB); (CC) Frequency(Hz)
Abstract:
A method and an apparatus for compensating a DC(Direct Current) offset and synchronization using a preamble signal are provided to detect a starting point of time of a preamble only by simple digital comparison computation. An offset detection circuit(30) includes a shift register(31), an accumulation unit(33), and a computation unit(34). The shift register sequentially receives digital conversion values acquired by digital-converting input signals in an over sampling ration of N time and stores the digital conversion values. The accumulation unit accumulates the latest N digital conversion values among the digital conversion values whenever the digital conversion values are inputted, and updates and stores the accumulation values. The computation unit determines whether or not a logic level of the input signal is shifted based on the accumulation values. The computation unit outputs an average value acquired by dividing the accumulation values by N in a DC offset level if the logic level is the input signal is shifted.