Analog to Digital Circuits
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Real-world measurement requires the extraction of weak signals from noisy sources. High common-mode voltages are often present even in differential measurements. The usual approach to this problem is to use an op amp or an instrumentation amplifier and then....
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The achievable accuracy for systems with multiple ADCs depends directly on the reference voltages applied to the ADCs. Medical- ultrasound- imaging systems, for example, commonly include a large number of ADCs in the system`s beam-former electronics, with....
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A practical realization of a spread-spectrum technique lowers a µP`s clock-related EMI by approximately 4 dB without the drawbacks associated with modulation (Figure 1). The spread-spectrum technique is a popular method to reduce µP-clock-related EMI....
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The first part of this article series discusses commonly known definitions most crucial for high-speed data converters (in this case analog-to-digital converter or short ADCs) used in communications, instrumentation and data acquisition applications. The....
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This in-depth article covers the theory behind a Delta-Sigma analog-to-digital converter (ADC). It specifically focuses on the difficult to understand key digital concepts of over-sampling, noise shaping, and decimation filtering. A description of new....
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The schematic in Figure 1 is the discrete-element version of an A/D-converter drive circuit. The circuit converts a single-ended input to a differential output. The ADC`s reference voltage determines the common-mode range of the differential outputs. The....
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By using two 8-bit ADC channels for the same signal, the technique in Figure 1 can accommodate both conditions. One channel, which the controller uses for fast motion, reads the input directly and adds four 0 LSBs for a 12-bit result. The second channel....
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Analog-to-digital converters (ADCs) represent the link between analog and digital worlds in receivers, test equipment and other electronic devices. As outlined in Part 1 of this article series, a number of key dynamic parameters provide an accurate....
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Since the late 1970s, designers have successfully improved the effective resolution and spurious performance of A/D converters by adding ditheruncorrelated noiseto a converter`s input and then using DSP techniques to average out noise from the converted....
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The circuit of Figure 1 shows how you can configure a FIFO memory, a static SRAM, and a bus register to generate fast hardware histograms for linearity tests and still allow straight data acquisition for other tests. The main purpose of the FIFO memory is to....
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ADCs with differential inputs are becoming increasingly popular. This popularity isn`t surprising, because differential inputs in the ADC offer several advantages: good common-mode noise rejection, a doubling of the available dynamic range without doubling....
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Manufacturers have recently introduced high-performance analog-to-digital converters (ADCs) that feature outstanding static and dynamic performance. You might ask, "How do they measure this performance, and what equipment is used?" The following discussion....
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This circuit was designed for measuring the current from a set of power trackers on the Iowa State University Solar Car, the PrISUm Phoenix. The power trackers provide impedance matching between the solar array and the main electrical bus on the car. Because....
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The LTC®1197/LTC1199 10-bit serial ADCs offer small size, low power operation and fast sample rates with good AC and DC performance. These parts are ideal for low power, high speed and/or compact designs. This Design Note discusses the features and....
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The new 14-bit, 800ksps LTC®1419 enhances new communications, spectral analysis, instrumentation and data acquisition applications by providing an upgrade path to users of 12-bit converters. It provides outstanding 81.5dB SINAD (signal-to-noise and....
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The LTC®1605 is a new 16-bit, 100ksps ADC from Linear Technology. Its outstanding DC accuracy and ±10V analog input range are ideal for industrial control and instrumentation applications. Its simple I/O, low power and high performance make it easy to design....
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Combining high speed analog-to-digital conversion with low power dissipation, the 500ksps LTC®1278 and 600ksps LTC1279 12-bit ADCs solve major challenges confronting designers of high speed systems: conversion performance, power dissipation, circuit board....
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Four new sampling A/D converters from Linear Technology stand out above the rest of the crowd. These new 5V and 3V 12-bit ADCs offer the best speed/power performance available today (see Figure 1). They also provide precision reference, internally trimmed....
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The following article takes the knowledge of advantages and disadvantages of the pipeline architecture and compares its features with four of the most popular architectures (flash, dual-slope, sigma-delta, and successive approximation) for analog-to-digital....
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If you use an ADC to monitor a system`s power-supply voltage, you may encounter situations in which the supply voltage exceeds the ADC`s reference voltage (Figure 1). However, the ADC`s input voltage cannot exceed its reference voltage. You can use an....
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Many noncontact temperature-measurement systems use infrared sensors, such as thermopiles, which can detect small amounts of heat radiation. Biomedical thermometers that measure the temperature of an ear or a temple use noncontact temperature measurement, as....
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Most current microprocessors, DSPs, and field-programmable gate arrays integrate hardware and software resources that support either or both of two common interface standardsSPI (serial-peripheral interface) and I2C (inter-IC)/SMBus. Both two-wire-interface....
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Flash analog-to-digital converters, also known as parallel ADCs, are the fastest way to convert an analog signal to a digital signal. Flash ADCs are ideal for applications requiring very large bandwidth, however, they typically consume more power than other....
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Integrating analog-to-digital converters (ADCs) provide high resolution analog-to-digital conversions, with good noise rejection. These ADCs are ideal for digitizing low bandwidth signals, and are used in applications such as digital multi-meters and panel....
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Many of today`s instrumentation and process control applications convert the analog output of a sensor for processing and/or storage using an analog-to-digital converter (ADC). For voltage input ADCs, three different input structure types exist:....
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Here is an inexpensive way to get slow-moving analog data directly into a spreadsheet on your computer! A simple circuit connects to a serial port and a short Qbasic program gathers and saves 12 bit data to a file. A spreadsheet automatically retrieves the....
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Flash-back to the 60's with this 5 channel unit with up to 100 watts per channel. This unit uses a PIC16F84 with an 8 bit A/D. The signal from both stereo channels is combined and digitized. Each of 5 frequency bands is processed using a 16 point FFT.....
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The analog to digital converter (ADC) is a commonly required in most of the projects. Analog voltage measurement can be done using the ADC hardware built in together in a PIC. The picture below show a simple setup for measuring the voltage through the....
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This circuit is a frequency meter, low cost. It covers region 1HZ until 1MHZ. The IC1 schmitt trigger that it regulates the signal of entry and him changes in reasonable level suitable for the IC2-3-4. With the tenth pulse in the entry of IC2/1, is produced....
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Study the Analog to Digital capabilities of Atmel ATtiny26. This tiny but mighty IC is really a miracle. One special thing is the internal 10-inputs multiplexed ADC circuit which can covert analog voltages to bytes. This check circuit uses only 3 inputs. Of....
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Normally analogue-to-digital con-verter (ADC) needs interfacing through a microprocessor to convert analogue data into digital format. This requires hardware and necessary software, resulting in increased complexity and hence the total cost.
The circuit of....
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This 4 1/2-digit DVM circuit is built around a Maxim ICL7129ACPL A/D converter and LCD driver. An ICL8069 CCZR 1.2-V band-gap reference diode is used for a voltage reference. S2a-b-c select one of four ranges up to 200 V (maximum). The meter also has a....