To: David G Michelson

From: EECE 380 Team L2D8

Date: April 6 2014

Subject: Project 2 Weekly Memo 9

Dear Professor Michelson,

This memorandum outlines the latest progress of the team for the week.

Achievements from Last Week

Our team assembled the crystal filter, amplifier and the peak detector altogether and tested the hardware as a whole. We also modified the LabVIEW software to run the local oscillator and display the signal spectrum using the waveform graph display. MyDAQ is connected to the hardware and it has two analog inputs coming in from the hardware. We run the program, observed the signal and debug the hardware all in the same time. Various frequencies were used and tested to ensure optimal performance of the hardware. In order to display the signal better in LabVIEW, we modified the offsets, signal run frequency and the number of samples run per second. We also tried to convert the signal to a log scale and convert the x-axis to frequency domain. To improve the peak display in LabVIEW, we monitor the discharge rate of the capacitor in the peak detector circuit.

Progress for this week

Both the hardware and software parts are assembled altogether and our team debug any possible problems may arise during the testing phase. We realized the signal spectrum was not displayed properly in LabVIEW, therefore we changed the offset and the scale of the axis. Different input frequencies and amplitudes were used to test the hardware, and we observed the displayed results in real time. We also ensure that the capacitors are discharged in a desirable time in order to improve the overall performance. After the final testing phase where the results are correctly displayed, we are ready for our project’s demonstration.

Problems and Improvements

Our team learned a lot throughout this project. We realized that sometimes the signal spectrum was not displayed correctly. This is because the Schottky diode was not connected properly in the circuit, which caused the capacitor to not discharge properly to produce a peak for the signal. The amplifier depends heavily on the values of the resistor we used. We biased the circuit and tested with different values of resistors using Multisim and Circuit Maker. We also observed the amplified voltage using the oscilloscope. In order to improve performance, we learned to calculate the right values of resistors to be used for the hardware.