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Envelope Filter Build Photos

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Week Seven – Reflection on Gibilisco Reading

Power Supplies, Bipolar Transistors and The Field Effect Transistor

I really want to build my own full-wave bridge rectifier circuit for a power supply.  I don’t think I will approach this for some time since the voltages could be lethal, and I’m not quite ready for such a build.  I did find a really nice book on building power supplies that is quite interesting and have started investigating how I might build a power supply for my synth rack.

Week Seven – Blacet Module Build Session

I started soldering my Oscillator module.  I finished the resistors and resistor networks when I noticed that my soldering tip started pitting and a good chunk of one side looked melted.  I decided to wait on more soldering until I can get my tip and soldering iron looked at.  Hopefully, I won’t have to buy a new unit.

Week Seven – MAX/MSP Build Session

After looking at the previous week’s design, I decided on a complete rebuild.  I wanted to make a smaller front end interface for all the modules.  I decided to model the design off of a guitar pedal MAX/MSP build that I had seen before.  All the modules seemed to be about the right size.  I decided to return to a simple patching matrix using umenu directly routed to one destination.  Visually, it should look a lot cleaner and will be readily usable.

Week Seven – Reflection on Lyons Reading

This week’s topic of sample rate conversion was immediately useful and understandable.  I really appreciated Lyons’ coverage of decimation and interpolation separately before showing how decimation and interpolation can be combined to create complex low pass filters.

Week Six – Blacet Module Build Session

This week, I spent my time reading over the documentation on my Module 2100 Voltage Controlled Oscillator.  I took a trip up to Alphatronics in Tukwila, WA to buy some new soldering iron tips, a tip cleaner and some braided hook-up wire.  I went over the parts to make sure nothing was missing and studied the board to become familiar with the layout and how I was going to approach the build for this module.

Week Six – MAX/MSP Build Session

This week, I spent a considerable amount of time adding VU meters and an amplitude control slider to each module. I also spent a considerable amount of time creating a patching matrix based on the EMS Putney.  The patching matrix did not function, and considering that I spent so much time devoted to a device that did not function, I am a bit behind in some of my other designs.

Week Six – Reflection on Gibilisco Reading

The reading from this week repeats what was previously read from week four/five.  Old material included semiconductors and diodes.  The new material consisted of a section on transformers and impedance matching as the final chapter covering alternating current.

The new chapter on basic electronics has really helped tie together how many of the parts I have been using in my electronics builds work.

Week Six – Reflection on Lyons Reading

Quadrature Signals and the Discrete Hilbert Transform

These two chapters completely lost me.  Lyons helps by pointing out the usefulness of these two subjects, yet do not see how I might use them in my future work with digital signal processing.

Week Five – Reflection on Lyons Reading

Infinite Impulse Response Filters and Specialized Lowpass FIR Filters

Chapters six and seven of the Lyons reading were extremely heavy.  The end of chapter six provided a good comparison chart of IIR filters and FIR filters and their differing characteristics.

At first I thought that IIR filters must be better then FIR filters because of their ability to simulate analog filters, it requires of the least number of necessary multiplications and it requires the least coefficient memory.  I think that both are very useful and that the hardware/software designer must choose carefully which really meets his/her needs the best.  Some applications may be better suited with FIR filters because sensitivity to filter quantization is low, hardware filter control is simple and the ease of design is simple as well.

Chapter seven really got into the use of specialized lowpass FIR filters.  Lyons goes into frequency sampling filters and interpolated lowpass FIR filters.  He states that the common thread between these two types is that they are very efficient computationally and are able to “…attain greatly reduced computational workloads compared to traditional Parks-McClellan-designed FIR filters…”