ELCN100 : Electronic Lab 1 Cairo University

ELCN100 Electronic Lab.

Instruments and MeasurementsSpring 2018

Lecture 08:Digital Instruments Basics (cont.)

Dr. Hassan Mostafa

حسن مصطفى. د

hmostafa@uwaterloo.ca

ELCN100 : Electronic Lab 2 Cairo University

Objective of this chapter

In order to study the operation, applications, and performance of Digital Multi-Meters (DMM), we need to understand the following blocks:

Basic logic gates

Flip-flops

Digital displays

Digital counters

Frequency dividers

Analog-to-digital converters

Digital-to-analog converters

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Digital Counters

Mod-10 counter

RRRR

ClkClkClkClk

R = Reset

When R = ‘0’, the flip-flop

output = ‘0’

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Digital Counters

Mod-2000 counter

BCD-to seven segment display drivers

3.5 digits display

3 complete digits and one flip-flop ON/OFF

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Analog-to-Digital Converter (ADC)

Ramp-type ADC

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Analog-to-Digital Converter (ADC)

Ramp-type ADC

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Example

The ramp-type ADC system uses a 1MHz clock generator and a ramp voltage that increases from 0V to 1.25V in a time of 125msec. Determine the number of clock pulses counted into the register when Vi = 0.9V, and when Vi =0.75V.

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Solution

The ramp-type ADC system uses a 1MHz clock generator and a ramp voltage that increases from 0V to 1.25V in a time of 125msec. Determine the number of clock pulses counted into the register when Vi = 0.9V, and when Vi =0.75V.

For Vi = 0.9V

Vi/Vr = t1/(t1+t2) -->

0.9/1.25 = t1/125msec --> t1 = 90msec

For a clock frequency of 1MHz,

the clock pulse period = 1/1MHz = 1usec

The number of clock pulses counted =

90msec/1usec = 90000 pulses

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Solution

The ramp-type ADC system uses a 1MHz clock generator and a ramp voltage that increases from 0V to 1.25V in a time of 125msec. Determine the number of clock pulses counted into the register when Vi = 0.9V, and when Vi =0.75V.

For Vi = 0.75V

Vi/Vr = t1/(t1+t2) -->

0.75/1.25 = t1/125msec --> t1 = 75msec

For a clock frequency of 1MHz,

the clock pulse period = 1/1MHz = 1usec

The number of clock pulses counted =

75msec/1usec = 75000 pulses

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Quantization Noise

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Quantization Noise

Quantization error = ± 0.5* VFS /(2n) = ± VFS /(2n+1)

VFS = Full scale voltage

n = number of ADC bits

2-bit ADC

quantization error of ± VFS /8 = ±12.5% of the full scale voltage

5-bit ADC

quantization error = ± VFS /64 = ±1.6% of the full scale voltage

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Course Project (15 marks)

Each group of students ( consists of 3-5 students) should select oneelectronic instrument from the following list and perform the following:

Send an email to (hmostafa@uwaterloo.ca) indicating the group members and their choice by Wednesday April 18, mid-night

Use Labview to build the instrument.

Deliver a hard copy report explaining all the steps of the design and several examples as well as user manual for their product.

Prepare and deliver a Youtube video showing their product similar to the below videos ( English or Arabic)

- https://www.youtube.com/watch?v=MrAH8fCWXXE

- https://www.youtube.com/watch?v=ZMPkOrXzaoU

- https://www.youtube.com/watch?v=hKiOQXfzdzI

List of Electronic Instruments:

Function Generator and Digital Scope

Digital Logic Analyzer

Function Generator and Digital Frequency Meter

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Course Project

Deadline of submitting the report and performing the presentations:

Wednesday (Last week) at lecture/lab time

Report (Hard Copy)

Video over email with subject “ELCN100 YouTube Video Link”

The group must appear in the video and their names should be clear on the end of the video for grading

Restrictions:

The report is maximum of 10-pages including the cover page

- <Each extra page receives -1 mark>

The video time is 5 minutes (Maximum)

- <Each extra minute receives -2 mark>

Delayed delivery of the group members names, reports, or video email receives a penalty of -3 mark/day.