MEMORANDUM

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: March 30, 2014

SUBJECT: Spectrum Analyzer Fourth Weekly Memo

We mainly focused on four components for spectrum analyzer project this week, peak detector, crystal ladder, amplifier, and LabVIEW. The first three parts are completed, and the software part is halfway finished.

The peak detector is used for detecting signal level peaks. The peak detector provided a DC output from the AC input of the resolution filter. Our group decided to use simple peak detector rather than precision one, because the high frequency op amp is unstable at 8MHz. A simple peak detector’s output is similar to a precision one, and it can work very well even at high frequency. The wire connection of a simple peak detector is simple. After calculating the values of the resistor and the capacitor, connect them in parallel, and then connect with a diode.

The next component is Crystal Ladder Resolution Band Pass Filter. The crystal ladder filter utilises Quartz crystal oscillators that have a resonant frequency of 8MHz. This allows us to build a band pass filter around the center frequency of 8MHz. The two crystals provided extra attenuation for the stop band and the capacitors improved the high frequency roll-off by adding extra poles. The band pass filter was tested by using tracking generator test set. Our group used online crystal ladder calculator to figure out the values of the capacitors and resistors, and then wired then up on the breadboard.

For the amplifier part, we used two LM6181 chips to build. We also chose the tantalum capacitors because these capacitors have high capacitance per volume and weight, lower equivalent series resistance, lower leakage, and higher operating temperature than other capacitors. Because we want the amplifier to have a better performance, the unique features of tantalum capacitors make them perfect for the project. The next step is to connect them on the breadboard based on the schematics we already designed.

The last task of this week is the LabVIEW programming. We have mapped out the entire program and are currently able to generate a  sawtooth waveform output from myDAQ to the circuit. We are also able to display input voltages and frequencies using the waveform and x-y graph functions in labVIEW. The main tasks left for completion are minor tweaks such as the conversion of the sawtooth waveform from voltage to frequency within labVIEW.

Sincerely,

EECE 380 L2B5

MEMORANDUM

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: March 23, 2014

SUBJECT: Spectrum Analyzer Third Weekly Memo

For the third week of our Spectrum analyzer project we preliminary discussed about the scope and goals of our project amongst our team. And divided task to individual team members hoping to complete the project more efficiently. This week we did not have a tutorial from TA, so we did researches online and asked previous rotations for more details of the project.

This week, we integrate and test several part of the project to gain a better understanding. First of all, we begin the designing of the RF switch and did researches on the similar function chip described in our projection description. Yet more researches need to be done in the future as we do not have any previous knowledge of an RF switch.

We also tested the crystal ladder res-bandwidth filter circuit. Base on the designs from the internet we were able to produce similar result to the band pass filter given in our kit. The crystal ladder bandwidth filter has a center frequency around 150 MHz and bandwidth of 50 MHz At this moment, we were not able to finalize our design as it depends on previous part of the project.

Our team also tested few simple peak detector design. The peak detector is used to acquire voltage readings from the output of the res band pass filter, currently we are using 20K Ohm resistor in parallel with a 220 Pico ferrite capacitor, and it is able to detect peak values from the signal generator up to 100 MHz and an amplitude greater than -20dbm. The values of the capacitor and the resistors are not finalized as the input was not determined. This integration was just to gain better understanding of the principles of the peak detector.

This week, we realizes the strong correlation between each part of the project, it is difficult to divide the project into parts and complete individually. Next week we will re-discuss our work distribution and draw out a better plan top- down.

MEMORANDUM

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: March 16, 2014

SUBJECT: Spectrum Analyzer Second Weekly Memo

On March 12^th, we had our second tutorial on spectrum analyzer project. The main topics covered were voltage controlled oscillator (VCO), RF Amplifier, mixers, and how to use the tracking generator. The most important step was to put everything together (e.g. Mixer – VCO – BPF).

First things first, we learned the concept of VCO. For example, what are the main features and applications of VCO, some electrical specifications are also stated in the tutorial. The purpose of the first lab activity was to familiarize ourselves with the VCO. Starting off by testing the VCO with the spectrum analyzer; set the Vcc to 12V DC, and set the current limit on power supply; use the DC power supply for Vtune.

The next component of this tutorial was the RF Amplifier, a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power. We learned some key features and applications of the RF amplifier; for example, it is wideband, and the frequency is from 0.05 to 500MHz. Moreover, some electrical specifications are also stated in the chart. The second lab activity was about the RF amplifier. We start off by testing the amplifier with an RF source and spectrum analyzer. Set the Vcc to 15V DC, and set the current limit on power supply; next, set the RF input to -40dBm and frequency to 100MHz. After the setup, we measured the gain of the amplifier at various frequencies, and determined what range is safe input power level according to the data sheet.

We will continue to finish up the lab activities next week, which is to put everything together. We will test the mixer using the VCO as LO, and observe the output with the spectrum analyzer. Next, we will notice the role of the filter in selecting the output of the mixer when it is connected to 10.7MHz band pass filter. Finally, set the RF to 50MHz and determine the VCO output we need to down convert the RF into the band of the band pass filter.

Sincerely,

EECE 380 L2B5

MEMORANDUM

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: March 8, 2014

SUBJECT: Spectrum Analyzer First Weekly Memo

We have moved on to our second project in this week, the spectrum analyzer. During the first lab on Friday, the TA gave us the first tutorial to familiarize ourselves with various lab equipment and the goals of this project. A spectrum analyzer measures the magnitude of an input signal according to its frequency. We also understood the main setting parameters on spectrum analyzer screen; for example, the axes, units, and how to adjust the machine. Another main component of this lab is the RF connectors. There are a variety of connectors based on different frequency, bandwidth, sizes, power levels; the main ones we will be using for this project is BNC, N and SMA connectors

After the TA introduced the main tasks and challenges of this project, we moved on to the first lab activity. We connected the RF source to the spectrum analyzer and adjusted the maximum output and input power levels. Then, we measured CW signals of different levels and frequencies, explored saving traces, and used markers to perform measurements. The primary aim of this lab activity is to get to know the spectrum analyzer which is the core of this project. During next week, we will continue finishing up the first lab activity and move onto the next lab

At this preliminary stage of the second project, our group will maintain the attributes that we did well in the first project, and improve our weaknesses. Due to that we are quite tight on time for this project; we will have a clear weekly schedule of what needs to be completed and a to-do list for the following week. The weekly leader is in charge of group meetings and writing memo. We will make sure that we keep everything organized and finish this project perfectly.

Sincerely,

EECE 380 L2B5

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: February 24, 2014

SUBJECT: Fifth Week

Summary In this week, our team has reached the final stage of our project. We calibrated the water level sensor, modifies the code, soldered the circuit, and installed the actuators. For the water level sensor, we poured the water into the cup and recorded the corresponding voltage, then we plotted the graph on Excel. We also had the line of best fit and the equation for the graph. Water level sensor acts as a capacitor, it connects to LM555 timer, which generates frequency. The timer then gives the signal to LM331, which converts the frequency to voltage. Finally, the voltage goes through LM358 op amp and sends the signal to the modem; the modem will then send the email to our gmail account. The other sensor for this project is temperature sensor, we soldered the entire circuit on a single solder board. For the actuators, we use LEDs and buzzer. We have six LEDs to tell us about the water level, and the buzzer buzzes when the water level goes above the threshold. For the temperature sensor, we set 20 degree Celsius as our threshold point, when the temperature goes above 20 degree, the green LED is turned on; when the temperature drops below 20, the yellow LED is turned on.

Sincerely, EECE 380 L2B5

It should be noted that this MEMO was submitted to the TA on time but uploaded late to the blog.

FROM: EECE 380 Lab Group L2B5

TO: Dr. Michelson and Lab TAs

DATE: February 2, 2014

SUBJECT: Second Week Summary

This past week, we successfully completed the DemoappGSM and DemoappADC program alterations. These programs were then combined to send a voltage from an analog pin on the Q4000 to our group email. It is important to note that the voltage was measured from analog 0 (pin 19), which required modification to the battconversion value. The biggest problem we encounter was the conversion from a double value, the voltage reading, to a char; this was necessary for the DemoappGSM to send the data to our email. We overcome this problem by ultilizing the sprintf function. It should be noted that the time frame between each email had a strong dependence on the position of the satellite and varied from 1 – 5 minutes. Before Wednesday lab session, we plan to revisit the DemoAppFFS, as our team encountered some problems with accurate execution.

Our top concept for the project was to monitor the water level & temperature of local rivers with the purpose of informing kayakers of the conditions. Currently, the best system is to watch kayaking forums for first-hand information or make assumptions based on local weather conditions. For the most part, kayakers don’t have accurate information until they’re at river ready to paddle.

Our idea is to change this by constructing a system of measuring the water levels on the river and temperature and relay the data to a GUI. The main concept of our idea is to keep the apparatus simple and module so it could be implemented in a wide variety of rivers with minor calibration required.

Sincerely,

EECE 380 L2B5