A tutorial on SAR type A/D converters, this note contains detailed information on several 12-bit circuits. Comparator, clocking, and preamplifier designs are discussed. A final circuit gives a 12-bit conversion in 1.8µs. Appended sections explain the basic SAR technique and explore D/A considerations.
Linear Technology offers a variety of devices that simplifyconverting power from a USB cable, but the LTC®3455represents the highest level of functional integration yet. The LTC3455 seamlessly manages power flowbetween an AC adapter, USB cable and Li-ion battery,while complying with USB power standards, all from a4mm × 4mm QFN package. In addtion, two high efficiencysynchronous buck converters generate low voltage railswhich most USB-powered peripherals require. TheLTC3455 also provides power-on reset signals for themicroprocessor, a Hot SwapTM output for poweringmemory cards as well as an uncommitted gain blocksuitable for use as a low-battery Comparator or an LDOcontroller. The PCB real estate required for the entire USBpower control circuit and two DC/DC converters is only225mm2.
該系統(tǒng)由單片機(jī)89S52控制模塊，程控寬帶放大模塊，整形模塊，F(xiàn)PGA內(nèi)頻率、相位差測(cè)量模塊等構(gòu)成，采用等精度測(cè)頻法測(cè)出頻率和周期，可測(cè)量有效值為0.01～5V，頻率范圍1Hz～20MHz信號(hào)的頻率、周期信號(hào)，精度高達(dá)10-6。采用計(jì)數(shù)法測(cè)量相位差，該系統(tǒng)可測(cè)量有效值0.5～5V，頻率10Hz～100kHz信號(hào)的相位差，精度為1°。系統(tǒng)功能由按鍵控制，測(cè)量結(jié)果實(shí)時(shí)顯示，人機(jī)界面友好。
Abstract:
The system consists of the following functional blocks:89S52microcontroller controlling module,programmable amplifier module,Comparator module,frequency and phase difference testing module in the FPGA.The system use the equal accuracy frequency-examining technique it measures frequency and circle of signal which its ranges is from1Hz to20MHz and the amplitude of which its range is from0.01Vrms to5Vrms,precision is up to10-6.Using of count method,the system detects the phase difference of signal,the amplitude of whic its range is from0.5Vrms to5Vrms and the frequency of which its ranges is from10Hz to100kHz,precision is up to1°,The system functions is controlled by certain keys,measurement results are displayed in real-time and it is friendly interface.
NEC 16位MCU參考手冊(cè)
The 78K0R/IC3 is a 16-bit single-chip microcontroller that uses a 78K0R CPU core and incorporates peripheral functions, such as ROM/RAM, a multi-function timer, a multi-function serial interface, an A/D converter, a programmable gain amplifier (PGA), a Comparator, a real-time counter, and a watchdog timer.
