The Si4840 and Si4844 from Silicon Labs are the first CMOS AM/FM/SW radio receiver ICs with analogue tuning and digital display that integrate the complete receiver function from antenna input to audio output. Based on Silicon Labs’ proven and patented digital low intermediate frequency receiver architecture, the Si4840 and Si4844 deliver superior RF performance and interference rejection. The integrated control algorithm provides an easy and reliable control interface while eliminating all of the manually tuned external components used in a traditional receiver. [via]
AM/FM/SW receiver integrated on a single CMOS chip - [Link]
An introduction to AM/FM active antennas: [via]
This article is a reference design (RD) for an automobile AM/FM active antenna. The RD presents the flexibility of the MAX2180 active antenna low-noise amplifier (LNA) and shows how to set the AM and FM gain and the automatic gain control attack point. Single and dual antenna schematics are detailed, including the input and output matching circuits. Using this design together with the data sheet and device’s evaluation (EV) kit, a prototype antenna can easily be developed for a wide range of active antenna requirements.
App note: AM/FM active antenna - [Link]
The Park Ranger is an ultrasonic-ranging prototype designed to assist drivers who are backing into tight areas. The ranger uses ultrasonic pings to measure distance to the object behind and indicates this distance by sending audible tones to your FM radio. Optional panel-mount LEDs offer visual aid for calibration as well as warning drivers behind you.
The intention of this project is to demonstrate the Amani64ʼs ability to serve as a rapid-prototyping tool for applications typically covered by proprietary modules. While a commercial ultrasonic-ranging module could be used in this project, the Amani64 is used in instead to tailor the system to our exact needs. The user can drop in blocks of IP, whether open-source or their own, to create a custom application over which they have full control and ownership. A CPLD-based prototyping board is useful for any application that requires logical circuits, whether they be parallel or sequential, that space, cost, and vendor-delivery times are a concern.
DIY Park Ranger – [Link]
Sean Michael Ragan writes:
This circuit is commonly credited to Japanese multimedia artist Tetsuo Kogawa. It takes audio input through a 1/4″ phono jack and, constructed as shown, without the optional antenna connections, will broadcast an FM radio signal about 30 feet.
Micro FM Transmitter – [Link]
Circuit of stereo FM transmitter of of high quality using integrated circuit ba1404 for mp3, mp4, ipod, computer, radio of the car. Transmit of your equipment of portable audio for the radio of your car, transmitters of fm of low potency are the ideal for transmission wireless of audio sign for fm receivers. Mainly in that case that is treated of transmitter of FM stereo with ba1404. The heart of that circuit is the circuit integrated ba1404, that is a mini fm transmitter, that already counts with the necessary internal circuits for transmission in fm. just being necessary to increase some components discman or any other audio source turning the wireless. If you already set up other transmitters of transistorized fm it will see that when setting up that with having integrated BA1404, that the quality of the sound and the frequency stability is excellent. Besides the but it presents easy assembly.
Stereo FM Transmitter with BA1404 – [Link]
This project creates a very tiny FM transmitter with only 17 electrical parts and then shows you how to stick it into a slightly modified mint box to create the ultimate FM Bug. The transmission range is up to 100 feet indoors and even more outdoors.
FM Bug Transmitter Mint Box – [Link]
This project provides the schematic and the parts list needed to construct a 3V FM Transmitter. This FM transmitter is about the simplest and most basic transmitter to build and have a useful transmitting range. It is surprisingly powerful despite its small component count and 3V operating voltage. It will easily penetrate over three floors of an apartment building and go over 300 meters in the open air.
3 volts FM transmitter – [Link]
This project is a stereo FM transmitter with RDS. The transmitter frequency is controlled by a Philips TSA5511 PLL IC through I2C communication. For the RDS part the author used a programmed RDS IC’s, the MRDS192.
Test stereo FM transmitter with RDS - [Link]
This project is a small USB mono FM transmitter with a range of about 50 meters. It is designed to be plugged on USB port and uses two FET transistors. Due to the power supply via the USB port, a high frequency stability is achieved.
USB Mono FM Transmitter – [Link]
This project is a high quality PLL FM transmitter with output power of 5 W. The transmitter includes RDS/SCA input and Audio/MPX input with optional pre-emphasis. It can be used with or without stereo encoder. Tuning over the FM band is provided by two buttons that control dual-speed PLL. The transmitter can work also without the LCD display.
5W PLL FM Transmitter – [Link]