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12 Mar 2014

What’s inside Tektronix’s new MDO3000 Mixed Domain Oscilloscope? Dave does a teardown and looks at the circuitry and how they can get such a cheap 3GHz RF spectrum analyser to work.

EEVblog #587 – Tektronix MDO3000 Mixed Domain Oscilloscope Teardown - [Link]

18 Jan 2014

Ever wondered how they transmit your TV signal?

David Kilpatrick from TXAustralia takes us on a detailed tour of the old decommissioned 10kW analog TV transmission system at the Artarmon facility in Sydney. It is still used to transmit digital TV. How it all works from the broadcaster video input to final transmission output up the 180m broadcast antenna. Plus some teardowns of the old equipment that’s been used to transmit the Channel 7 TV signal in Sydney since 1981.
Copper rigid coaxial lines, waveguides, filters, splitters, combiners, converters, transmission valve, power supplies and all the equipment necessary to transmit a 10kW analog or digital TV signal in a major city like Sydney.

EEVblog #569 – Tour of an Analog TV Transmission Facility - [Link]

20 Nov 2013

Ray Wang writes:

Hi, I recently built a reflow toaster oven using an Arduino. I know it’s pretty standard stuff, but my version has an automatic oven door opener (using a servo) and circulation fan to speed up the cooling time, and remote notification using an RF transmitter

[via]

Reflow toaster oven using an Arduino - [Link]

13 Nov 2013

article-2013october-understanding-the-basics-of-low-noise-fig3

By Bill Schweber:

In a wireless design, two components are the critical interfaces between the antenna and the electronic circuits, the low-noise amplifier (LNA) and the power amplifier (PA). However, that is where their commonality ends. Although both have very simple functional block diagrams and roles in principle, they have very different challenges, priorities, and performance parameters.

How so? The LNA functions in a world of unknowns. As the “front end” of the receiver channel, it must capture and amplify a very-low-power, low-voltage signal plus associated random noise which the antenna presents to it, within the bandwidth of interest. In signal theory, this is called the unknown signal/unknown noise challenge, the most difficult of all signal-processing challenges.

Understanding the Basics of Low-Noise and Power Amplifiers in Wireless Designs - [Link]


20 Aug 2013

article-2013aug-selecting-rf-connector-wireless-system-fig2

By Bill Schweber

The explosive growth of “wireless” systems has led to a simultaneous expansion in the use of RF connectors and their associated cables. These assemblies are increasingly vital links between multiple circuit boards, between antennas and front ends, and between power amplifiers (PAs) and antennas. They are instrumental to the operation of such wireless devices and systems as cellular telephones, wireless data networks and advanced radar and electronic-warfare (EW) systems.

Connectors for RF systems have the simple yet critical task of transferring signals from one location to another, with little or no change to the signal (although in reality even with high quality RF cable between the antenna connector and the antenna engineers often factor in a 0.2 dB loss per coaxial connector in addition to the cable attenuation itself).

Selecting an RF Connector for your Wireless System - [Link]

18 Jun 2013

article-2013may-tune-in-charge-up-fig2

by Publitek European Editors:

In today’s wireless, connected world, ambient Radio Frequency (RF) energy is everywhere. Technically, this free-flowing energy can be captured, converted and stored for use in other applications. In fact, it is already in use in a number of ultra-low-power, battery-free applications, such as RFID tags, contactless smart cards, and wireless sensor networks. As a result of technological advances, harvested RF energy is just beginning to realize its wider potential, including charging batteries in smartphones and other portable devices. These enabling technologies include RF transceivers, power conversion circuits, and ultra-low-power microcontrollers, all of which are becoming ever more efficient.

Tune In, Charge Up: RF Energy Harvesting Shows its Potential - [Link]

5 May 2013

Analog Devices, Inc. (ADI) released a new version of its popular ADIsimRF design tool:

The free design tool is the software accompaniment to ADI’s complete portfolio of RF-to-digital functional blocks, allowing engineers to model RF signal chains using devices from across ADI’s RF IC and data converter portfolio. ADIsimRF Version 1.7 adds a number of new device models along with enhanced support for inter-stage mismatch calculations. The design tool provides calculations for the most important parameters within an RF signal chain, including cascaded gain, noise figure, IP3, P1dB, and total power consumption. The ADIsimRF design tool contains embedded data from many of ADI’s RF ICs and data converters, which designers can easily access using pull-down menus to assist in component selection.

[via]

Analog Devices releases free version of RF design tool - [Link]

25 Apr 2013

IMG_1485

by Dave Rishavy & Tomas Berghall:

The one piece of gear that’s essential for EMC troubleshooting is a spectrum analyzer. You can buy a decent portable for about $10k or used ones go for $1k to $5k if you don’t mind the 30 to 80 pounds of weight or the initial investment. This article reviews several models that cost under $2,000.

Compare low-cost spectrum analyzers - [Link]

29 Jan 2013

LDO_noise

Glenn Morita writes:

The difference between insignificant noise and significant noise is the degree to which the noise affects the operation of the circuit in question.

For example, a switching power supply has a significant amount of output voltage ripple at 3 MHz. If the circuit it is powering has a bandwidth of only a few hertz, such as a temperature sensor, this ripple may be of no consequence. On the other hand, if the same switching power supply powers an RF phase-locked loop (PLL), the result could be quite different.
Understanding the sources of noise, their spectral characteristics, noise reduction strategies, and the sensitivity of the circuits in question to this noise is crucial to successfully designing a robust system.

This application note also attempts to clarify the difference between power supply rejection ratio (PSRR) and internally generated noise, and describes how to apply the data sheet specifications for each parameter.

Noise Sources in Low Dropout (LDO) Regulators - [Link]

29 Jan 2013

dtt1-500x335

This is a TV transmitter to generate a stream containing four TV programs and broadcasts it on a frequency in the DTT standard.
Ideal for stacking in an antenna system, audiovisual channels generated on-site or from other sources like a decoder for satellite television.

With this project you can make a small local TV station that has up to four TV channels. You can also integrate into a system into other existing TV signals that will be transmited on a desired RF channel. It’s ideal for exclusive cable installations for a condominium, a hotel, company premises or public place.

This merges 1 to 4 television channels in one stream of output that is ready to be transmitted on air (with the help of a linear RF) or injected in a localized cable TV circuit.

Using DTT to create your own TV transmitter - [Link]



 
 
 

 

 

 

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