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FM Radio Circuits
FM Radio Circuits
FM modulation circuit diagram using ceramic resonator
On frequency stability, the quartz crystal oscillator circuit is very advantageous, even the the VCXO circuit with large amount of frequency changing only changes about 1%, and the linear range of control voltage to frequency variation is not wide. Although the ceramic resonator Q value is lower than the quartz crystal oscillator, the inductive...
Mini FM Transmitter
FM Transmitter is very simple, compact, and has transmission signal with a range of 100-150m, good sensitivity and low current consumption. Transmitter`s schematic consists of a bass amplifier for the first transistor and the proper frequency generator in the second. FM Transmitter divided transitional capacitor that allows you to set up a...
PLL FM Transmitter using LMX1601 ATtiny2313 AT90S2313
Here`s a PLL FM Transmitter using LMX1601, ATtiny2313 or AT90S2313 microcontrollers. The common characteristic of all of the previous low power FM transmitters I`ve built over the decades, is that their operating frequency is determined by an LC resonant circuit. Some of them had excellent stability, some of them didn`t, but I had always wanted...
PLL Stereo FM Transmitter
The circuit shown here is of a good Stereo FM transmitter that can transmit high quality signals up to a range of 70 feet. The circuit is based on BH1417 PLL stereo transmitter IC from Rhom semiconductors. The IC has separate audio processing sections for the left and right channels, pre emphasis circuit for improving signal to noise ratio, crysta
Quality FM transmitter circuit
This house FM transmitter for your stereo or any other amplifier provides a good signal strength up to a distance of 500 meters with a power output of about 200 mW. It works off a 9V battery. The audio-frequency modulation stage is built around transistor BF494 (T1), which is wired as a VHF oscillator and modulates the audio signal present at...
Stereo FM Transmitter Using BA1404
A high quality stereo FM transmitter circuit is shown here. The circuit is based on the IC BA1404 from ROHM Semiconductors. BA1404 is a monolithic FM stereo modulator that has built in stereo modulator, FM modulator, RF amplifier circuitry. BA1404 FM transmitter can be operated from 76 to 108MHz and power supply for the circuit can be anything...
Stereo FM Transmitter circuit with BA1404
With this Stereo FM Transmitter with BA1404 you will be able to create a mini stereo FM station and broadcast to your entire home, a simple way to have an audio link wireless with ease. With the FM transmitter BA1404 Hifi Stereo you can stream your music from your iPod MP3, satellite receiver, computer, DVD player, Mobile Phone, MP4 player and...
The PLL FM modem circuit
USB Mono FM Transmitter
This small FM transmitter with a range of about 50 meters designed for connection to the USB port. With lots of mini-transmitters then you have a comprehensive, action-packed radio program. Due to the power supply via the USB port of a high frequency stability is achieved. Alternatively, the receiver, a battery 5 to 12 volts to operate. FM...
VHF FM Transmitter MAX2606
If you want to be independent of the local radio stations for testing VHF receivers, you need a frequency-modulated oscillator that covers the range of 89.5 to 108 MHz ? but building such an oscillator using discrete components is not that easy. Maxim now has available a series of five integrated oscillator building blocks in the MAX260x series...
iPod FM Transmitter
Building your own ipod FM radio transmitter. It works quite easy, there is a power switch on the bottom to turn it on and tune your radio and transmitter to the right frequency. For the antenna you can use a copper wire of 70 cm. The range of this FM transmitter is about 100 to 150 meters (500 feet). With R5 you can adjus
FM TUNE UP
At some point every ham working with FM radios has need to do some tuning of the transmitter and receiver. If you are like me and lucky enough to have professional test equipment, this task is easy. If you don`t have access to professional equipment, you just have to be a little more clever. Note that a good deal of what I have to say here applies
Single Chip FM Transmitter For Short Range Application
The FM transmitter circuit here works in the broadcast band 88 to 108MHz, and can be used to broadcast audio signals for remote listening. The output power..
PLL FM Demodulator
PLL (Phase Locked Loop) can be used to make a FM demodulator. PLL circuit track the input frequency by controlling a voltage input of a VCO (Voltage-Controlled..
Two Transistors FM Transmitter
Basically, this circuit is a radio frequency (RF) oscillator that operates around 100 MHz. The audio which is picked up and amplified by the electret..
Ratio Detector for FM Demodulation
This view is not far from wrong because the operation of FM detectors is widely regarded as mysterious. The ratio detector to find out how it works, without..
XR2211 Linear FM Detector
This is a linear FM detector circuit. This circuit usually is used in telemetry applications and wide range of analog communications. The main part of this..
Voltage Controlled Oscillator for Commercial FM Band
VCO (voltage controlled oscillator) is an electronic signal generator which produce a signal that has variable frequency depends on a voltage level at its..
50 kHz FM Optical Receiver
Frequency modulation (FM) can be used to transmit analog voltage level signal with good noise immunity. The transmission itself might employs different..
Frequency Modulated Oscillator (for FM Transmitter)
An oscillator can be built using LC (inductor-capacitor) tank circuit. When we vary the capacity of the capacitor in LC tank circuit then the frequency of the..
The FM broadcast band was moved immediately after World War II from its original spot just below 50 Mc to the present 88-108 Mc band. Hallicrafters was one company to offer receiving converters for those who had the old FM radio sets. The offerings included a one-tube converter that fits inside a console and draws power from the audio output tube
Low Tech FM Radios
Broadcast band frequency modulation (FM) radio was invented to solve existing problems with noise and fidelity on the amplitude modulation (AM) broadcast band. Thus, the first FM receivers were quite complex in design, employing a superheterodyne converter, a wideband IF, a limiter stage, and a discriminator. Unlike the first AM radio sets, the ea
One transistor FM radio project
For this project the 1 1/4 meter Midland 13-509 ischosen, mainly because it`s use in several (transparent) links, which support the SRG 147. 20 repeater. First strip out several items not needed or otherwise to improve reliability and performance. That would include the T-R relay, the receiver deck, most or all of the trimmer capacitors for the...
Crystal Locked FM Bug
A number of simple FM devices, (without the use of a crystal) and showed how the power and frequency depends on a number of factors including the voltage of the supply and the design of the stages. The broad term given to the oscillator stage of these transmitters is "voltage dependent" as the frequency of the output is dependent on the voltage...
am fm radio tuner multiplex decoder
FM Transmission and Reception
The original f-m transmitters manufactured by the General Electric Company were the direct f-m type employing the regular electronic automatic frequency control system similar to that discussed in connection with the CBS transmitter. The f-m multiplication system in these original transmitters employed two triplers for a total frequency multiplica
This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The coil is four turns of 18swg wire wound around a quarter inch former. The aerial tap is about
Long Range FM Transmitter
The power output of many transmitter circuits are very low because no power amplifier stages are incorporated. The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts. With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, thi
fm stereo transmitter ba1404 diagram
Circuit FM transmitter for MP3 and MP4 Player 2n2218 and 741 opamp
Evolution FM transmitter with 2n2218 with audio amplification step using LM741 op amp with audio input for MP3, MP4, mobile, computer and other audio sources, beyond the traditional electret microphone. With great sensitivity to the input signal. Using fewer components and easy assembly makes it ideal for those who want even without much experienc
Circuit of power fm transmitter transistor 2n2218 audio wireless 1KM
This small transmitter can arrive the more than 1 km in favorable conditions of emission. The modulation can be made so much with a microphone, for an electrets microphone, or other audio source. The 5 turns of enameled thread 22 AWG, with diameter of 1 cm without nucleus. Look at the capacitors that it should be ceramic. The antenna should posses
RF Transmitter Circuits
RF Receiver Circuits
RF Amplifier Circuits
AM Radio Circuits
FM Transmitter Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
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