The team has now spent 2 weeks considering the various blocks involved in building the spectrum analyzer. The team mates were assigned different tasks based on their skills.

Hardware:

The goal of the hardware sub-team this week was to finalize the resolution BW filters and the peak detectors as well as determine what amplification is necessary. The resolution BW filters were constructed by using crystal oscillators which were centered at 8 MHz. Two filters needed to be built and so two BWs were decided upon while considering the standard conventions for spectrum analyzers. In order to “flatten” the bandpass region, the gain of the filter was sacrificed. Minor adjusting is still needed however as the BWs are not equal to what was planned.

The design for the peak detectors was finished and circuiting of these designs started this week. Due to faulty breadboards however, the peak detectors were not finished this week.

A test BJT amplifier was constructed to simulate the amplification of signals with very low dBm. The amplifier does not work within the required operating range and thus some adjusting is still needed.

Next week will focus on finishing the peak detectors, video filters and amplifiers as well as adjusting the resolution BW filters. Once this is complete, the hardware components can be integrated and tested as a whole.

Software:

The software sub team worked towards achieving the design specifications. The sub team implemented the user interface for the spectrum analyser after designing the ramp to ouput the right voltage range. The user interface includes traces and markers to help the user to compare different signals and to find the magnitude of signals.

The team used LabView to build a signal diagram to send the ramp input to the VCO and to use the input from the hardware sub team to create x-y plots. Further, the team implemented controls to change sweep time and to switch between traces. Control for the markers was also implemented, this allows the user to measure the magnitude of the signal at different frequencies.

The team had to research ways of displaying multiple graphs on the same plot and to enable/disable each graph separately to allow the user to pause graphs and interpret the data. We used the array builder to combine the signals from two xy graphs and plot them in Lab View.