To: David G Michelson

From: EECE 380 Team L2D8

Date: March 16 2014

Subject: Project 2 Weekly Memo 6

This memo summarizes the progress from the first tutorial to the thrid tutorial. In time span, it includes the material from March 7th to March 14th.

What we learned so far

In the first tutorial, we familiarized ourselves with the spectrum analyzer and the signal generator. We also learned to set up NI myDAQ, data acquisition device. The first tutorial was pretty preliminary. In the second tutorial, we were asked to test different components. We found out that the gains of components are as follows:
Frequency Mixer
-7 dB
RF Amplifier
22 dB
Band Pass Filter
-0.7 dB
Attenuator
-10 dB
In theory, the signal right after the RBW filter will have a very small gain of 4.3 dB. We connected everything with a 0 dBm 50 MHz signal and the peak value was observed to be around 5 dBm which is very close to the theoretical value. Particularly, we noticed that the output signal of VCO is 0 dBm instead of typical 10 dBm on the datasheet, and the final experiment also proved us right. In the third tutorial, we spent most of our time finishing up the second tutorial, but it clearly showed us what we need to do next week.

Problems Identified

The problem is that the local oscillator can only produce signals between 40MHz and 80MHz due to the voltage output limit of myDAQ. The most likely solution is to build an amplifier to amplify the voltage of ramp signal to the desired range. The other problem is that the high frequency band pass filter we have right now is centered at 10.7 MHz. To get 8 MHz center frequency, we need to find some solutions.

Work Ahead

Try thinking about solution for measuring modulation index or frequency deviation.
Try searching the solutions to adjust the center frequency of band pass filter to 8MHz.
Hardware wise: Two sets of crystal filters are needed. Two sets of high frequency peak detectors are needed. One transistor amplifier with gain around 1.4 is needed.
Software wise: In the LABVIEW, use block diagram to plot the data acquired from ramp generator and peak detector. Try to add the switch for the crystal filter.

To: Dave Michelson

From: EECE380 Team L2D8

Date: 2 February 2014

Subject: Project 1 Weekly Memo 2

INTRODUCTION

This memo summarizes the completion status of last week’s goal and this week’s task. It also includes the plan for the next week.

LAST WEEK’S GOALS

We successfully sent the email using satellite, and modified ADC code last week. It was planned that we should be able to send voltage readings in the emails this week. The other minor remainder of last week was to change subject line of the email. The subject line was manually changed using PuTTY command window, but the ability to change it in C code remains to be explored. On January 29th, we used CFG_Write to change the configuration parameter which is related to the subject line of the message. After debugging several errors, we managed to change the subject line to what we need. On January 31st, we combined ADC code and ORBCOMM code to send voltage readings in the emails. A floating-point number was received by the email.

THIS WEEK’S TASKS

Due to the security reason and availability of the satellite, we need to save the messages in the flash before we send it. There are two ways to approach this, one using FFS, the other using ORBCOMM saving messages commands. The other objective of this week is to familiarize ourselves with the timer on board. Later on, we may need a timer to do timely event like saving data and sending messages.

NEXT WEEK’S GOALS

First, use timer to send emails with ADC voltage readings regularly. Second, create an OSI packet, save it on board, and send it. Third, save the packet which contains voltage readings on board, and send it.