Archive for the ‘Signal Generators’ Category

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 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 […]

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 […]