Lab 5 Signal Analyzer/Generator

Introduction  Create a client MFC application that samples a signal and displays wave using Windows GDI, Open GL, or DirectX.  Digitally analyze and generate analog waveforms  Reconstruct the waveform using the sampled signal

Spartan 3 board Tutorial 1 Tutorial 2 Tutorial 3

Acquiring an Analog Signal  Input is a signal with peak to peak of 5 V  Voltage input in the range -2.5 to 2.5 V  Use Analog to Digital Converter ADC0820 Input’s analog voltage 0 to 5 V Requires adding 2.5 Volts to input signal before converted.

Voltage compatibility issue  Spartan 3 uses a 5 V adapter  Internal voltage levels are 3.3 V, 2.5 V and 1.2 V.  ADC0820 needs a 5V, Output levels are close to 5V  Inputs cannot handle 5 V without a current limiting resister.  Use R > 170 Ohms to limit current to 10 mA.  Alternately, since the FPGA I/O are TTL compatible, you may want to use TTL buffers to limit the voltage levels to about 3.4 V.

Sampling Signals on Serial Port  Max Baud Rate 115, ,200 bits per second  Max Sampling Frequency 115,200 / 10 bits (8 data, 1 start, 1 stop)  Max Input Frequency to avoid aliasing (Max Sampling Frequency) / 2 = 5760 Hz

Discrete Fourier Transform (DFT)  Can be processor intensive thus use Fast Fourier Transform (FFT) to calculate DFT  Algorithm requires a sampling frequency as a power of 2  Refer to FFT function on UL-99 (C++)

Windows GDI If you took 408 you probably already know this

Device context classes  CPaintDC - for drawing on windows client handlers (on paint only)  CClientDC - for drawing on windows client handlers (anytime other then on paint)  CWindowDC – for drawing anywhere in a window  CMetafileDC - Drawing to a GDI metafile

How to draw  Create paint object  Move to point  Draw line

How to draw  CClientDC DC(this)  DC.MoveTo(0,0);  DC.LineTo(100,100);  When the window calls on_paint the window will clear the area.

How to keep a drawing on a screen  Void draw(CDC* pDC,CRect rect)  { pDC->Rectangle(rect)  }

How to keep a drawing on screen  Onpaint()  { CRect rect; GetClientRect (&rect); CPaintDC dc(this); draw(&dc,rect);  }

Other draw functions  Rectangle  Arc  PolyLine  MoveTo  Pie  Ellipse  RoundRect

Coordinates taken from programming with MFC second edition

Coordinates  How to set  CClientDC dc(this)  dc.SetMapMode (MM_LOMETRIC);

Why you should use a pixel coordinate systems and pitfalls  There are only so many pixels on a screen, this is set by a screen resolution.  In a pixel coordinate system, how many pixels on a client window can be found by finding the size by using:  GetClientRect(CRect rect);  1 pixel is the most accurate there is (no such thing as ½ pixel in GDI)

Changing Color  CPen pen;  pen.CreatePen (PS_SOLID, 1, RGB (255, 0, 0));  CClientDC dc(this)  CPen *oldPen = dc. SelectObject(&pen);

Changing Color Taken from programming with MFC, Second Edition

Different Lines Taken from programming with MFC, Second Edition

Draw Text  CPaint dc(this)  dc.SetTextAlign(TA_RIGHT);  dc.TextOut(0,0,”hello”);

Anything else?  THERE IS MORE YOU CAN DO  This is just on the basics  Anything other details can be found on the MSDN.