Direct Digital Synthesis (DDS) Explained by [Bil Herd]

One of the acronyms you may hear thrown around is DDS which stands for Direct Digital Synthesis. DDS can be as simple as taking a digital value — a collection of ones and zeroes — and processing it through a Digital to Analog Converter (DAC) circuit. For example, if the digital source is the output of a counter that counts up to a maximum value and resets then the output of the DAC would be a ramp (analog signal) that increases in voltage until it resets back to its starting voltage.

This concept can be very useful for creating signals for use in a project or as a poor-man’s version of a signal or function generator. With this in mind I set out here to demonstrate some basic waveforms using programmable logic for flexibility, and a small collection of resistors to act as a cheap DAC. In the end I will also demonstrate an off-the-shelf and inexpensive DDS chip that can be used with any of the popular micro-controller boards available that support SPI serial communication.

All of the topics covered in the video are also discussed further after the break.

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Autonomous Quadcopter Fits in the Palm of your Hand

[Horiken Engineering], which is made up of engineering students at the department of aerospace at the University of Tokyo have developed an autonomous quadcopter that requires no external control — and its tiny. By using two cameras and a sonar sensor, the quadcopter is capable of flying by itself due to its ability to process the data from the on-board sensors. To do the complex data processing fast enough to fly, it is using a Cortex-M4 MCU, a Spartan-6 FPGA, and 64MBs of DDRSDRAM. It also has the normal parts of a quadcopter, plus gyros, a 3D printed frame and a 3-axis compass. The following video demonstrates the quadcopter’s tracking ability above a static image (or a way point). The data you see in real-time is only the flight log, as the quadcopter receives no signal — it can only transmit data.

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