12 BIT ADC RESOLUTION CALCULATOR SOFTWARE

Let x be the distance in cm and let y be the resistance in kohm. The linear potentiometer distance sensor exhibits linear behavior.Д¬heckpoint 14.6: Consider the linear potentiometer in Figure 14.2.

12 BIT ADC RESOLUTION CALCULATOR SOFTWARE

You can use a simple circuit to convert resistance to voltage, the ADC to convert voltage to an integer, and simple software Software will have an easy time with a linearД®xample, the linear potentiometer, PTA20432015CPB10, hasДЄ transfer function as shown in Figure 14.2, where the input x is distance in cm, and the output y is resistance in kО©. In other words, the input/output response fits a linear equation: A wide variety of inexpensive sensors can beДЇunction fits a straight line. Signal paths a data acquisitionДЄ transducer converts x into y. What is the corresponding time interval? I.e., how many seconds of sound can you play?ДЇigure 14.1. Assume you allocate 128 kibibytes out of the available 256 kibibytes of ROM to store the data. You can pack two DAC samples into one byte. What is the corresponding time interval? I.e., how many seconds of data can you record?Д¬heckpoint 14.5: Assume you have a 4-bit DAC used to play sound. Assume you allocate 20,000 out of the available 32,768 bytes of RAM to store the data. Give a formula that relates needed memory in bytes as a function of fs and T.Д¬heckpoint 14.4: Assume you have an 8-bit ADC. Let fs be the sampling rate in Hz, and T be the total time interval required to collect samples in sec. Give a formula that relates the resolution, dX as a function of Xmin, Xmax and n.Д¬heckpoint 14.3: Assume you have a 12-bit ADC and store data into an array of type uint16_t. Give a formula that relates the precision in bits as a function of Xmin, Xmax and dX.Д¬heckpoint 14.2: Assume the precision is n in bits, and Xmin, Xmax, and dX are all given in the same units.

If we use a memory buffer with 500 elements, thenД¬heckpoint 14.1: Assume Xmin, Xmax, and dX are all given in the same units. To sample the ADC and calculate distance, the sampling rate, fs, is 10 Hz, and the time quantization is 1/ fs=0.1 sec. Time interval is the smallest to largest time during which we collect samples. Time quantization is the time difference between one sample and the next. In most systems, the resolution of the measurement is determined by noise and not the number of bits in the ADC. Theoretical resolution is 1.5cm/4095, or about 0.0004 cm. If there is no electrical noise and we use a 12-bit ADC, then the If a system has 12-bit precision, there are 2^12 or 4096 distinct alternatives.ДЇor example if we use a slide pot to measure distance, the range of that pot might be 0 to 1.5cm. The units of precisionДЄre given in alternative or bits.

The following four limitations exist when sampling data.ДЄmplitude resolution is the smallest change in input signal that can be distinguished.ДЇor example, we might specify the resolution as dX.ДЄmplitude range is defined as the smallest to largest input value that can be measured.ДЇor example, we might specify the range as Xmin to Xmax.ДЄmplitude precision is defined as the number of distinct values from which the measurement is selected. Consider an entire system that collects data, not just the ADC. System has no actuator because it simply measures the measurand in

Measurand in the real world to a desired value while the data x(t) is the time-varying signal we are attempting to measure. Figure 14.1 shows the data flow graph for a data Like sound, distance, temperature, force, mass, pressure, flow, lightДЄcceleration. To measure distance to an object (EE319K skips this).

Use the Central Limit Theorem to improve signal to noise ratio.

Theorem to cases where we use the ADC to sense information. Quantization, range, precision and resolution. Transducers: conversion of physical to electrical.Дigital computer to sense its analog world. We define the rate at which we sample as the sampling rate, and use the symbol fs.ДЄDC, software, PWM output and motor interfaces to implement intelligent Interrupts to sample the ADC at a fixed rate. More specifically, we present a technique for theДЄnalog inputs using an analog to digital converter (ADC). This chapter we will focus on input devices that we use to gatherДЄbout the world. System uses its input/output devices to interact with the external Throughout this course we have seen that an Modified to be compatible with EE319K Lab 8 14: Analog to Digital Conversion, Data Acquisition and Control

12 bit adc resolution calculator