by brmarcum @ instructables.com:
I got the idea for this circuit from one of my professors at Washington State University. However, the frequencies used in that project would not have allowed for passing higher frequency audio, e.g. 2kHz+. So I built this by modifying the carrier and signal frequencies, using only the Digilent Analog Discovery and the Analog Parts Kit. It should be noted that this circuit is primarily for educational purposes. Also note that there is no radio transmission here either. FM doesn’t necessarily mean radio waves have to involved.
Throughout this Instructable I will be going through some of the functions and features of the Analog Discovery, but it will not be an exhaustive tutorial.
FM Modulation/de-modulation Circuit - [Link]
lamefreaks @ instructables.com writes:
In this instructable I’m going to show you how to build your own portable audio transmitter. This transmits FM waves so you could easily get the signals on your mobile phone, radios, etc. As the name and the picture indicates it is very small and is approximately the size of a 9v battery clip.
Mini Audio Transmitter - [Link]
Bluetooth® Low Energy (BLE) may not be part of your electronic designs just yet, but chances are it will be soon. This wireless connectivity technology has experienced explosive growth over the last three years. It now provides low-power connectivity to millions of electronic devices, such as smart watches, fitness trackers, smartphone accessories, and medical monitors. Thanks to upcoming technical enhancements, BLE is poised to become even more pervasive in the next generation of consumer electronics and the emerging Internet of Things.
Many of the enhancements have been incorporated in Bluetooth 4.1, a recent update to the core specification. Among them are support for more efficient bulk data transfers, greater flexibility in communications between devices, simultaneous dual-mode roles, and the first steps toward IP-based communications. Taken together, these technical improvements make BLE even more attractive from power consumption, performance, and cost standpoints.
In addition to the enhancements outlined in Bluetooth 4.1, the BLE chips themselves have been continuously improving. Thanks to efficiency improvements, transmission power consumption in the second generation of BLE will fall by about 66 percent with no loss of range or performance.
Moving Forward With Bluetooth Low Energy - [Link]
As promised we have built a transceiver USB dongle, for receiving data from various sensors like, smart meters, smoke detectors and temperature/humidity sensors. We’ll provide some code examples on how this trasciever can be used, and software for decoding data from diferent sensors enumerated above.
USB RF 433.92 MHz Transceiver module - [Link]
The filter shape of an HF bandpass filter that is designed for the 30m amateur radio band (10MHz) is measured using a Tektronix MDO3000 mixed domain oscilloscope. The arbitrary function generator (AFG) is used to generate a noise waveform that is flat across the HF spectrum, and the filter shape is then shown on the spectrum analyzer. The filter being measured is the front end bandpass filter of a Softrock Lite II SDR receiver kit.
How to measure an HF Bandpass filter response with the MDO3000 - [Link]
To my computer, its simply a USB keyboard, nothing less, but to me its a remote I can use on any platform with no line of sight. I decided to name it the keyMote. Sounds a bit odd to my ears but its a fitting name.
Here is how it works. There are two parts to this system, the remote, which is battery powered, and the base, which is hooked up to a computer. The remote is a simple keypad (In the case of the prototype, its a numeric keypad, but really, it could be any interface) with a transmitter hooked up to it. The base, the other end, is a receiver with USB Human interface device functionality, in other words, a vanilla USB keyboard. When a button is pressed, the remote sends the identifier of that button to the base which then looks up in a table the keystrokes this identifier is mapped to and sends those to the computer via USB. What button is mapped to what keystroke is entirely configurable using a serial terminal interface (shell) to the base. It can be anything, Ctrl-C, Alt-Shift-F, PageUp, etc. Getting it to interface with your program is then simply a matter of configuring keyboard shortcuts.
keyMote: a simple wireless remote for computers - [Link]
An introduction to why and when terminations are needed for transmission lines in both high speed digital applications and RF applications. 50 ohm termination examples are given, but the principles apply for other line impedances as well. The basic operating principles of signal propagation down a transmission line and the effects of reflections coming from improperly terminated are covered. Examples for digital-like signals as well as RF signals are given. A description and examples of what is meant by Standing Waves is also given. As a bonus, the properties of quarter wavelength transmission lines in RF applications is also presented.
Transmission Line Terminations for Digital and RF signals - [Link]
High-performance RF signal source family offers AM/FM/Phase modulation with I/Q modulation option
Fairport NY: Saelig Company Inc. (www.saelig.com) has introduced a high-performance RF signal source family, the DSG3000 3GHz/6GHz series, offering standard AM/FM/Phase modulation, as well as options for I/Q modulation and I/Q baseband output. The DSG3000 Series generates waveforms with high signal purity, typical phase noise of less than 110dBc/Hz@20kHz, and a wide output range of -130dBm to +13dBm. The DSG3000 RF signal generator has standard pulse modulation with an on/off ratio of up to 80dB, with an optional pulse train generator also available. The DSG3000 series has a typical amplitude accuracy of better than 0.5dB, and the standard 0.5ppm internal clock can be upgraded to an optional 5ppb high stability oven-controlled clock.
The DSG3000 series RF signal generators support internal and external modulation capabilities and operate with USB, LAN, LXI-C, and GPIB remote control interfaces. They also feature a wear-free electronic attenuator design and an automatic flatness calibration function via external automated power meter control over USB. This can be used as an automatic flatness calibration test system functionality for cables, attenuators, amplifiers, etc. The DSG3000ʼs standard 2U height is designed to save space when used with the optional rack mount kit.
Offering remarkable value for the money, the DSG3000 Series RF source is ideal for applications in wireless communication, radar test, audio/video broadcasting, as well as for general purpose, educational, and consumer electronics needs.
DSG3000 Signal Generators are made by RIGOL Technologies, a rapidly growing test and measurement company and the worldʼs second largest oscilloscope manufacturer by volume. RIGOL delivers high quality, high performance and value-priced test equipment for engineers, technicians and students worldwide. Offered with a remarkable 3-year warranty, the DSG3000 series is available now from Saelig Company, Inc. 1-888-772-3544 firstname.lastname@example.org
Saelig Announces Economical 3GHz/6GHz RF Signal Generator Series - [Link]
mcuoneclipse.com explains how to use the HC-06 Bluetooth Module. They write:
After my first post using a Bluetooth module, things have evolved a bit. The challenge with these Bluetooth modules is: they look the same, but having different firmware. I did not fully realize that until I have ordered another bluetooth module from dx.com: That module comes already on a carrier, so I assumed I can use the same driver as for my other module. I was wrong :-(.
HC-05 or HC-06
My earlier module which I received from another source (without an adapter, see this post) has a different firmware on it, known as HC-05, while my DX.com module has a HC-06 firmware. To be clear: the modules are the same, but the software/firmware on it is different, and the firmware uses the pins differently too
Using the HC-06 Bluetooth Module - [Link]
Admittance control, movement of goods, tickets for various cultural events and sport matches, travel tickets, parking,… thanks to a permanently lower price and bigger possibilities of RFID cards (tags) the Mifare system (13,56 Mhz) in various variations runs forward even to segment where an older 125 kHz system didn´t suite. Complete RFID solution for a very affordable price, it is a short summary of RFID modules features from company Stronglink, which we already introduced to you in several articles.
Group of modules SL03x – SL030, SL031 and SL032 represents complete OEM RFID modules with antenna integrated on a PCB, intended to be built into an end device. All these three modules support Mifare Mini, Mifare 1k, Mifare 4k, Mifare Plus and Mifare Ultralight. SL032 further supports also the DESFire protocol. SL030 has an I2C communication interface, while the SL031 and SL032 have a UART. Modules are controlled by a set of simple commands, thus an integration into a device should cause no troubles even to less-experienced developers.
Thanks to a close cooperation with a producer, we aim to keep a sufficient amount of STRONGLINK RFID modules in stock.
SL030, 031, 032 … Mifare RFID available for you - [Link]