In this episode Shahriar explores the world of Delta-Sigma modulators with emphasis on a Delta-Sigma Analog to Digital Converter (ADC). The basic concepts of analog to digital conversion is presented, particularly with respect to quantization noise spectral shape and power density. Next, oversampling ADCs are presented to demonstrate the possibility of increasing SQNR (ENOB) through manipulation of quantization noise spectrum.
Due to the practical limitations of high oversampling ratios, delta-sigma modulations is explored. The principle operation behind delta-sigma ADCs is presented with detailed explanation on noise shaping, filtering and decimation. The signal and noise transfer functions for a 1st order and 2nd order delta-sigma ADC are derived. Finally, as a practical example, a 2nd order delta-sigma ADC based on a 1-bit quantizer is presented. The ADC uses two Miller integrator op-amps, one comparator and a D-Type flip-flop. The complete measurement of this delta-sigma ADC is presented. The impact of over sampling ration, op-amp linearity and input signal bandwidth is presented. The slides for this video can be downloaded from The Signal Path website.
Theory, Design and Characterization of Delta-Sigma Analog to Digital Converters - [Link]
In our portfolio can be found quality knobs from company Cliff suitable for a wide range of potentiometers and encoders.
A device with excellent specification, quality components used, …., but a one step is still missing to reach a great overall impression – it is to use a quality and aesthetic control components.
Probably you´ll agree, that knobs for potentiometers and encoders belong to a “group of critical components”, determining a resulting look of a device. Company Cliff specializes on development and production of these components already from 1977 and considerable experience are reflected in a precise construction and a wide portfolio of components produced.
● K87MAR – plastic two-color knob with a colored top part and a side line. Available in 8 standard color versions. Thanks to a big popularity and a mass production, their price is very affordable. User friendly, soft – “rubber-feel” surface. Excellent for color coding of potentiometers groups in equipment with many knobs. 6mm „D“ shaft.
● K87MBR – plastic two-color knob, very similar to series K87MAR, but only a side line is in color. Affordable price and a mild “rubber-feel” surface. 6mm splined shaft or 6 mm “D” shaft.
● K18 – universal plastic knob for electronic encoders. Available in 5 colors and 3 weight categories. In our stock can be found 2 heavier versions (35 and 50g) in a grey and black color.
● KMK – universal aluminium knob with a machined aluminium shell and a molded plastic inner. Available in a black or natural anodized surface. Push-on installation. In our stock can be found 4 versions with a 25 mm diameter – KMK25 in a black and silver (natural) color, with a 6mm splined as well as “D” shaft.
Types for splined arbors have 3 relatively robust juts (as visible on a Picture), that´s why they´re suitable only for potentiometers with deeper splines, or with a lower splin count. From our offer they´re suitable for example for Taiwan-Alpha potentiometers and they´re not suitable for potentiometers Piher series PC16.
Cliff knobs – a pleasure to touch - [Link]
Warren Young of Tangentsoft writes:
Experienced audio DIYers are familiar with monolithic linear regulators like the 78xx series and the LM317. Here’s a simplified block diagram of a standard linear regulator, from National Semiconductor’s Application Note 1148
Let’s see… We have an op-amp, a couple of transistors, a voltage reference, and a few resistors. Can we build a linear regulator from these individual components? Yes, we can!
Op-Amp based linear regulators - [Link]
Microchip Technology Inc has introduced a PIC32 Bluetooth starter kit. The kit includes a board with a PIC32 microcontroller, HCI-based Bluetooth radio, Cree high-output multi-color LED, 3 standard single-color LEDs, an analog 3-axis accelerometer, analog temperature sensor and 5 push buttons for user-defined inputs. In addition the PICkit™ On Board (PKOB) eliminates the need for an external debugger/programmer and supports USB connectivity and GPIOs for rapid development of Bluetooth Serial Port Profile (SPP), USB and general-purpose applications. To support Bluetooth audio the starter kit also includes an interface for a plug-in audio CODEC daughter card set for release at a later stage.
Microchip Bluetooth Starter Kit - [Link]
by Joel Williams @ joelw.id.au:
I bought Avnet’s $49 Spartan 3A development board but it was discontinued not long afterward – right about the time when I decided I needed a few dozen more. I’ve since done some extensive research (thanks, Google!) to find a comparable thrifty thrill.
When choosing a development board, consider what you get with it and what you want to use it for. FPGAs are ideal for use with high speed peripherals, and in general it is much easier to buy a board that contains the part you want, rather than trying to add one on later (and inevitably giving up and upgrading to a more capable board).
Cheap FPGA Development Boards – What to look for - [Link]
It’s holiday season and the chances are some of your gadgets will be also be going along for the ride. The ThinkPower mobile charger by Zettaly has been designed to provide essential recharge capability for USB-charged devices when you find yourself any distance from a mains wall outlet. The ThinkPower itself can be fully charged in just 90minutes and once charged its 10,000mAh high-capacity battery pack can recharge any USB-powered gadget. It has been tested with iPhone, iPad, Samsung Galaxy, Nexus, HTC, Moto, LG, GoPro and many other brands of smartphones, tablets, and cameras (for DIY fans its also tested been tested with the Raspberry Pi :). A fully charged ThinkPower has enough capacity to recharge an iPhone 5 over four times.
Speedy Recharger - [Link]
by TONY DICOLA @ learn.adafruit.com:
Have you heard about small Linux-based development boards like the Raspberry Pi or Beaglebone Black, but been confused about which one is best for you? This guide will compare the specifications, performance, power usage, and development experience of four popular Linux-based development boards to help you choose which is right for you!
Embedded Linux Board Comparison - [Link]
Around June of 2012, I had gotten myself into a very bad habit. Instead of carrying my SD card in my camera, I left it sticking out of the side of my laptop, presumably intending to do something with the photos on it eventually. On my flight home from Boston, the predictable thing happened: as I got up out of my seat, the machine fell out of my lap, and as the machine hit the ground, the SD card hit first, and was destroyed.
I was otherwise ready to write off the data stored on that device, but something inside me just wasn’t happy with that outcome. Before I pitched the SD card in the trash, I took a look at what remained – as far as I could tell, although the board was badly damaged, the storage IC itself was fully intact (although with a few bent pins).
Reverse Engineering a NAND Flash Device Management Algorithm - [Link]
ReturnZero published a stroboscope build:
At its heart, a stroboscope is just a rectangular wave generator hooked up to a light source. I wanted a few extra features to make it nice to use:
Ability to set flash rate by either frequency or RPM
Set duty cycle of output without affecting flash rate
– 2×16 for displaying RPM, frequency and duty (one per line, so one will be hidden at any time)
Rotary encoder (with button) for main interface
– When button is not pressed, knob will increase/decrease the value of the selected digit
– When button is pressed, rotating knob will scroll through display digits
Buttons for quickly halfing/doubling thirding/trebling the flash rate
– This is useful for checking that you haven’t hit on a multiple of the rotation rate
Nice beefy output stage for switch big sets of LEDs
DIY stroboscope - [Link]
herpderp shares his waveform generator:
Here is my last project, a tiny waveform generator based on my previous project and some components:
– An AD9834 (DDS chip with sinus/triangle output)
– 2 x AD5310 (10bit DAC: one for the Vpp control, another one the offset control)
– 3 x LM7171 (Fast OPA)
– 3 x LT1616 (switching regulator: +5V, +7V, -7V)
This waveform generator is directly powered by a standard 12V jack and is capable of outputting a 10Vpp signal at 1MHz (between -5V and +5V, sinus waveform, no load). Above 1MHz, the output starts fading, reaching only 9Vpp at 4MHz (maximal frequency). Frequency, amplitude and offset are digitally controlled through the smart TFT.
Three “basic” waveforms are provided: sinus and triangle, coming from the DDS chip (0.1Hz to 4MHz, 0.1Hz step), and PWM coming from the microcontroller (0.1Hz to 1MHz, variable steps).
Tiny waveform generator - [Link]