Posts Tagged ‘DDS’

Direct Digital Synthesizer (DDS) (Part 9)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Let’s go a few steps further in the direction of a fully featured arbitrary wave generator ! The early posts describe how to generate clean waves at various frequencies. In this post, I will explain how to offset the signal and how to attenuate it. Setting negative offsets requires… negative voltage ! Which Arduino  platforms do […]

Direct Digital Synthesizer (DDS) (Part 7)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 A recent project lead me to excavate a quite old DDS design which may be of some interest for you. Instead of using a ladder of resistors, this design features a simple, cheap and yet powerful digital to analog converter. I will later explain why I choose this particular Microchip circuit but for […]

Pending publications

Summer is over. Apparently a lazy period of time, in reality, time for retrospection, thoughts and projects making ! For me it has also been a time for getting inspiration from various European places, other ways of living, travelling, enjoying arts and culture. Whoever will identify this place will get… my highest consideration ! [Mail] […]

Direct Digital Synthesizer (DDS) (Part 6)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Patrick, thanks for your feed back. Thanks to you, there will be some updates of the PlainDDS library and its related MicroDDS applications. Here is a quite simple but already pretty effective human-machine interface for driving a signal generator. Get the latest Flash Player to see this player. [Javascript required to view Flash […]

Direct Digital Synthesizer (DDS) (Part 5)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 This is an update in the status of PlainDDS library. After revising the code and trying some suggestions made by Arduinoos visitors, I performed some intensive tests from which I have been able to draw some conclusions: – The bits setting must be executed as quickly as possible in order to keep the […]

Fast Fourier Transform (FFT) (Part 5)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 So far so good, we got our magnitude spectrum. We may now analyze it just like any other spectrum in order to get meaningful information. In our case, we may want to identify the main frequencies from the spectrum. Firstly we will run a peak picking algorithm in order to locate major peaks, and […]

Direct Digital Synthesizer (DDS) (Part 4)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Encoder library + LCD libray + DDS library + some more code = MicroDDS! MicroDDS is a fancy little device which will allow you to generate multiple types of wave: Flat, Sine, Square, Triangle, Saw tooth, Random. The hardware is limited to an Arduino Board, 1 LCD (2 lines, 16 characters), 1 rotary […]

Direct Digital Synthesizer (DDS) (Part 3)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Here we go for some measurements obtained from the previously described Direct Digital Synthesizer. Measurements have been performed using a Rigol DS1052E Digital Storage Oscilloscope (DSO), originally 2 channels/50 Mhz, which has been uprated to 100 Mhz (See how here). The Channel 1 (yellow plot) probe is attached to the end point of […]

Direct Digital Synthesizer (DDS) (Part 2)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Now that we have the hardware ready, let’s go for the firmware! Firstly, we need a reference table containing wave data points. In our case, we will use a 256 steps table. In the context of this project, the content of this table will change depending on a wave type option: apart from […]

Direct Digital Synthesizer (DDS) (Part 1)

Part 1, 2, 3, 4, 5, 6, 7, 8, 9 Direct Digital Synthesizer (DDS) is a type of frequency synthesizer used for creating arbitrary waveforms from a single, fixed-frequency reference clock. The principle of operation is fully and nicely expained here. This post describes how to turn Arduino in a pretty attractive DDS with a few external components. Hardware There are two options […]