FM Radio Circuits
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If you`re the sort who`d like to have an HF receiver in every room, but can`t afford it, this idea is for you. It will also appeal to the beginner wishing to build the simplest possible direct conversion receiver. Using a readily-available FM wireless.... -
A block diagram and a schematic of the receiver are shown in Figures 2 and 3, respectively. In Figure 3, L6 and L7 are spaced 0.6 inch for a loss of about 0.5 dB. Q4 is the first RF amplifier. L9 and L10 are spaced about 0.8 inch with a partial shield.... -
The electronic diagram of the monophonic FM receiver made with TDA7088T is shown on Pic.4.12. If built with SMD components it can be placed in a matchbox, altogether with two button-type batteries. The operating principle of this device is given in the.... -
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The circuit is a common form used in FM transmitters. The transistor conducts for 60-90 electrical degrees. When it turns off the LC tank `rings`, completing the sinusoidal waveform coupled to the antenna. The circuit is 77-85% effecient, compared to 40-50%.... -
P1 act as condenser microphone volume level. For FM, coil will be small. Use thin gauge enamel magnet wire. the diameter of coil will be a couple mm: use ink tube from pen to form, and try 8-12 turns. Small inductance coils make for much guess work. Tags: 1..... -
This mini audio amplifier will test the audio stages in amplifiers such as the front end of FM bugs. You can also use it on lots of our other projects as well as the output stages of radios. It is a very handy piece of test equipment and will make a perfect.... -
Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and.... -
This article explains the specifications and characteristics of crystals and crystal oscillators, and aids in specifying crystals and working with crystal vendors. The article covers the significant performance characteristics of crystals, which include.... -
This Design Idea presents a low-cost method of generating the basic 19-kHz pilot tone. The 19-kHz pilot tone comprises a baseband signal, and the L+R and LR signals consist of DSBSC (double-sideband-suppressed-carrier) modulation centered at 38 kHz. For a.... -
This is a wide band signal strength meter circuit which responds to small changes in RF energy, designed to be used for the VHF spectrum and will respond to AM or FM modulation or just a plain carrier wave. This circuit measures radio field strength by.... -
There have been a lot of transistor tester circuits in recent electronics magazines, but this one is different. It has more features and includes a signal injector so you can test audio sections of radios and the front end of FM transmitters etc. The major.... -
A project required an inexpensive oscillator whose frequency increased step by step from 200 to 400 Hz and then decreased to 200 Hz. The first step was to design a VCO with a staircase driver. However, this approach entailed at least four ICs and many....
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This circuit shows an active antenna that can be used for AM, FM, and shortwave (SW). On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna. This circuit is designed to be used on receivers that use untuned wire antennas,.... -
Crosstalk from digital data signals into the clock signal of a data-conversion system can cause hard-to-diagnose problems. This obscure problem is different than the crosstalk from digital data signals into the analog signal path, which was the subject of....
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What is the effect of digital signal bits cross-talking into the analog section of a data-conversion system? There is a lot written into the data sheets of ADCs and DACs on how to minimize it. But, when asked what is the result, most laymen have the insight....
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The DS1602 and DS1603 from Dallas Semiconductor offer a simplified hardware solution for keeping time as well as tracking powered up time of a system. The DS1602 and DS1603 can be read and written directly by a microprocessor or microcontroller using simple....
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This design idea describes a simple circuit to generate a programmable negative control voltage. It takes the output of a single supply digital-to-analog converter (DAC) and produces a variable negative voltage. The DAC output from 0V to +2.5V is converted....
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The transmitter output drivers present a low impedance to inbound surges and must be able to drive sufficient current in the primary of the transmit transformer in order to produce the required output pulse at the network interface. The receiver inputs....
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In an R-2R DAC design with supply voltages exceeding ±5V, large voltage glitches (up to 1.5V) can occur during the DAC`s major-carry transitions. These glitches can propagate through the output buffer amplifier and appear at output. The slewing of the level....
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Despite the popularity of digital devices, real world signals are typically represented by analog signals. Digital control systems process real world analog signals by using an analog-to-digital converter (ADC) to convert analog signals to digital.....
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The dual, voltage-output DACs shown in the figure below employ a combination of power-conserving tricks to draw less than 20µA from a 5V supply. The circuit suits a need for programmable voltage generation in slow or static applications, such as the nulling....
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This article discusses application circuits for Maxim force/sense digital-to-analog converters (DACs). Applications include: selectable fixed-gain DAC, programmable gain DAC, photodiode bias control, amperometric sensor control, digitally programmable....
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A laser module designer can use a fixed resistor, mechanical pot, digital pot, or a digital-to-analog converter (DAC) to control the laser driver`s modulation and bias currents. The advantages of a programmable method (POT or DAC) are that the manufacturing....
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The µPC8211TK, µPC8215TU, and µPC8226TK are silicon germanium (SiGe) microwave monolithic integrated circuits (MMIC) designed as low noise, high-gain amplifiers for GPS and mobile communications. These ICs are manufactured using our 50 GHz fmax UHS2 (Ultra....
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What is the effect of crosstalk from the digital data signals into the clock signal of a data-conversion system? This is a more obscure problem than crosstalk from digital bits into the analog signal path, which was the subject discussed in the previous....
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The synchronous oscillator (SO) and the coherent phase-locked synchronous oscillator (CPSO) are universal multifunctional networks that track, synchronize, and amplify as much as 80 dB; improve SNR by as much as 70 dB; and modulate AM, FM, and FSK signals...
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This application note uses a timer IC (ICL7555), CMOS logic and discrete transistors to automatically control the conversion the MAX190 12-bit SAR analog-to-digital converter (ADC). The delay between conversions can be programed using a resistor. Logic....
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Using a 12-bit-resolution analog-to-digital converter (ADC) does not necessarily mean your system will have 12-bit accuracy. Sometimes, much to the surprise and consternation of engineers, a data-acquisition system will exhibit much lower performance than....
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The MAX125 and the MAX126 are complete 14-bit data-acquisition systems in which four of eight inputs are tracked and held simultaneously (Figure 1). An on-board sequencer allows the user to program which four (or fewer) channels are to be digitized.....
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This article describes an automated data collection system for analog-to-digital converters (ADCs). It discusses the advantages of automating data collection as well as a detailed description of the hardware and software. It goes on to explain the operation....
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The MAX104 processes analog input bandwidths that exceed 2.2GHz with 8-bit resolution. It sets a new standard for performance in high- frequency, high-bandwidth digital communications receivers, digital oscilloscopes, and high-speed data-acquisition systems.....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
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.... -
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.... -
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.... -
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.... -
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,.... -
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.... -
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.... -
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.....
Popular Circuits
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