This tag marks questions related high frequency (radio) circuits.

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-1
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0answers
40 views

13.5 MHz amplifier 20 W

I need to design an amplifier that takes a 13.5 MHz signal (10 mW, 1 Vpp) and amplifies it to 20 W for a coil. I'm thinking I'll use an op-amp to drive a Mosfet, but I don't know much about designing ...
1
vote
3answers
63 views

ESR of Ceramic Capacitor

I have been doing a bit research on ceramic capacitors, as I need one for the output of my synchronous buck converter. And as its very common that ESR is not straight forwardly given in the data ...
1
vote
2answers
66 views

What kind of a wire can we use for frequencies up-to 1Mhz and up?

I have been reading about wires in Wikipedia What am I doing? I am reading about wires thinking that I could by my wide knowledge with bunch of reading be capable of creating simple 8-bit or 16-bit ...
0
votes
1answer
59 views

PCB track width for MHz frequency

I am designing an DC to AC converter operating at 10MHz. Its a low power converter and the input current is under 2A. What PCB trace width should I use and can someone give me a guideline on how to ...
1
vote
0answers
104 views

Operational Amplifier frequency problem

I am using an operational amplifier in an inverting configuration with a gain of 10. (-R2/R1= 10), with a high cut-off frequency of almost 30 Mhz. However, while testing whenever I apply an input ...
0
votes
1answer
41 views

Where and how do I put an inductor on a volume control

I built an stereo equalizer but I made some mistakes. As the potentiometers didn't fit on my PCB I had to put them separated and make the connections with some wires. The other mistake is that I made ...
4
votes
2answers
149 views

Amplifying a high frequency signal of 30 Mhz or above using OpAmps

I am testing a 34 Mhz amplifier in an inverting configuration with a gain of 20. The cutt-off freqeuncy of amplification stops almost at 15 Mhz , which is very low. I want it to continue up to 27 ...
0
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0answers
85 views

IR2110 LTspice - High frequency switching

I am simulating a mosfet gate driver (IR2110), at high frequency (1MHz), in an half bridge configuration, feeding an induction load. My design is based on an IRF application note (AN 978). The ...
17
votes
5answers
6k views

Is this true: “At over 700 Hz, current simply flows over your body”?

I have heard this in a movie clip. I was just curious to know, is this really true? Because the one thing that I do know, is that at a high voltage, the current decreases, so that it doesn't harm a ...
1
vote
2answers
105 views

Opto-coupler base connection speed influence

I am using a 4N25 opto-coupler for 5kHz to 10kHz application. In some datasheets the turn on and turn off times are mentioned to be 3us. I am wondering if this opto-coupler is suitable for my ...
0
votes
1answer
96 views

High Frequency, High Power Amplification

I was wondering if anyone could give me a little information on amplifiers. What would be the best way to amplifying a small, 1v @ 1mA, very high frequency signal (3-5MHz) to a high power signal? The ...
1
vote
1answer
39 views

Simple question on high bandwidth Opamp reproducing low frequency signals

So if one were to use a high bandwidth Opamp, at say 10GHz, and use it to reproduce a much lower frequency signal, say in 1GHz or 700MHz, would there be attenuation or degradation of the signal?? Or, ...
0
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0answers
61 views

Amplifying Signals to a Certain Voltage

Say I have some high frequency low signals and I want to amplify them to peak at +/-9V or something. Yet the chosen Fully Differential Opamp is only powered at 5V. So even if the Opamp were to go to ...
2
votes
3answers
84 views

Feasibility of recovering radio transmission carrier frequency

Assuming you have an FM Radio transmission at 94.4MHz where the carrier frequency is generated by a rather accurate source (lets assume allan deviation \$10^{-12}\$), is it feasible to recover a sine ...
5
votes
2answers
949 views

Trace Length Tolerance Calculation - High Speed PCB Design

I have to interface a video format converter with a ADC IC, which converters RGB analog data to digital. The connection between this ADC and Converter is a 20 bit data bus which clocks at about ...
1
vote
0answers
86 views

Very high frequency out of SPI pin in ATmega16A

I was trying to interface ATmega16A with ENC28J60, and I was facing problems with it, so I decided to physically look at the signals b/w the master µC and the Ethernet chip using an oscilloscope. But ...
2
votes
1answer
113 views

Ground plane and an impedance-controlled signal trace

I'm laying out a PCB for a project that has an HD-SDI input, which uses a 1.5GHz signal. I'm new to high-frequency considerations, so I'm struggling with a few concepts. Here is the schematic and ...
3
votes
1answer
146 views

How do I find spectral purity?

How is spectral purity measured? or evaluated? I have this signal coming from a 10 MHz crystal oscillator. I know how to calculate the SNR, but how do I calculate the spectral purity? Is it also a ...
4
votes
5answers
1k views

What components or circuitry exist that can provide extremely high speed, accurate clocks?

I've been curious for awhile now about doing some high speed projects, such as measuring time differences of radio wave reception, and was wondering if there exists components that provide clocks much ...
0
votes
0answers
111 views

Colpitts vs. Hartley?

What are the pros and cons of using a Colpitts or a Hartley configuration for an oscillator?I know that the difference between them is the form of feedback, but does one or the other perform better ...
3
votes
1answer
160 views

Crystal oscillator problem

Here is the datasheet of the crystal (32 MHz) that I use for a MCU. The right layout is an older version of my board which totally works fine. The left one is the newer version where I placed the ...
0
votes
1answer
255 views

How do I troubleshoot this high-frequency PWM fan control circuit?

I have a 230 Volts fan from EBM papst. It is a fan that can be controlled through a PWM signal (between 1 and 10 kHz). I have built the circuit that is in the manual (see image) I did get this ...
4
votes
1answer
143 views

Capturing data at 500MHz

I have an ADC sampling at 500MHz (It is collecting data from an Ultrasound sensor). I need to be able to stream this data to my PC (for the time being - this will be done through a wireless unit). I ...
0
votes
2answers
101 views

Trouble with CE BJT amplifier

I have the following circuit : It is meant to amplify signals in microvolt range and around 100 MHz. Now in the figure, the transistor is an ideal one. So it works fine and as expected. But as soon ...
4
votes
2answers
246 views

Driving 74HC logic with sub-nano second clock reference

My goal: I am trying to phase lock a 74HC-based digital circuit from a clock reference at 10~15MHz pulse repetition rate. The pulse width is around 400 picosecond. The peak voltage is sometimes below ...
0
votes
2answers
73 views

Physical Layer: How do how frequency sources work?

This is likely basic: but how do the source that rapidly generate 0-1s thru a channel "work" so fast? If it is a electric signal that is the source [as it is I believe even for fiber optic where a ...
2
votes
0answers
178 views

Can I build a high-frequency SMPS choke out of an arbitrary coil of wire?

Suppose I want to build a boost converter that runs at 100 kHz, with an input voltage of 600VDC and an input current of 100 amps. (This is hypothetical, I know the semiconductors involved would be ...
1
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2answers
279 views

High Frequency Logic Level Conversion

I am using Arduino DUE for my project which gives a 3.3 volt output signal. I have to convert it to 5 volts to use it with another device. The problem is that my signal frequency is 1 MHz. I have ...
3
votes
1answer
146 views

Switching power supply using faraday cage and EMI protection?

Several switching power supplies in the market use this kind of cages to protect the circuit, however, i have this question, A) Is this used as a faraday cage due to the high frequency used by it? ...
1
vote
1answer
113 views

Why is the Litz Wire twisted?

I understand that dividing a wire into multiple insulated pieces reduce the Eddy Currents, and that reduces the magnetic field inside the wire, which leads to increased skin depth. But why do they ...
2
votes
0answers
61 views

Protect ADC - Input HF

I use an 7 GS/s ADC to acquire data with an frequency of 2 GHz. The input range of the device is between -0.35 and 0.35 volts. My signal is also between this range, but sometimes there is a short ...
0
votes
2answers
72 views

High frequency signal switch [closed]

I am trying to make a digital switch for a high frequency digital signal. As it's a voltage controlled switch, I am thinking of just using a MOSFET for it. What I am confused about is the bandwidth of ...
1
vote
2answers
606 views

How to design an square wave Oscillator Circuit with 1-20 MHz range?

I need a circuit that will generate square waves in a range of 1 to 20MHz. The circuit also should be adjustable in a scale of 0.05MHz for each step. There is no need for adjustments during the ...
0
votes
1answer
109 views

Will this H-Bridge and it's driver work?

I am creating a half bridge, I though about it a bit and came up with this idea First for the controlling side we have a typical 555 timer wired up like this (But the resistors are variable ...
1
vote
2answers
187 views

How to make a RF Additive Mixer for two inputs in same frequency band?

One of the most common designs for a SSB modulator (phase shift method) involves an additive mixer as the very last stage. Here is a block diagram for reference: This additive mixer must provide ...
0
votes
2answers
450 views

I2C at 2.4 MHz with five microcontrollers over 2 meters

I have five Teensy 3.1 and I would like to interface them with I2C running at 2.4 MHz. The maximum Line Length will be around 2 meters. Will it work? What's the best way I can wire this up? ...
2
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5answers
2k views

Very high speed counter (around 1.5 GHz to 2 GHz)

I am thinking of a device that can measure the distance of an object from a sensor using a radio transmitter and receiver pair. I'm thinking of using a counter at the sensor side, with a ...
0
votes
3answers
121 views

Capacitor on line with high frequency digital signal?

Capacitors act as a short for high frequency signals. If I place a capacitor on a digital 5V PWM line or perhaps a motor encoder line does the cap still act as a short to ground for the square wave ...
2
votes
1answer
283 views

What does this capacitor do? (Microwave biasing circuit)

I'm wondering what \$C_B\$ attached to the bottom of \$R_{C2}\$ does. This is a screenshot from a textbook called RF Circuit Design: Theory and Applications by R. Ludwig And P. Bretchko. Looking at ...
0
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2answers
500 views

Can I amplify high frequency signal?

I have found this awesome Raspberry PI FM transmitter project. It uses RPi GPIO pin to simulate FM signal. After some filtering to smoothen it, this could act like a real transmitter. But at this ...
0
votes
1answer
360 views

Why do we use S-parameters for High frequency signals?

I have read at numerous places that S-parameters are used for analyzing systems which deal with high frequency. But why only high frequency? From what I have read, I have understood the following ...
21
votes
4answers
1k views

At what frequencies does PCB design get tricky?

I have designed many mixed-signal PCB's where the highest-frequency component is the microcontroller's crystal oscillator itself. I understand the standard best practices: short traces, ground ...
3
votes
1answer
378 views

Metcal: why do they heat with HF?

I got a used Metcal station from ebay for my home-lab and everything I read about soldering with it is right, it is a completely different feeling. I understood that stuff about controling the ...
5
votes
5answers
533 views

Which parameters in datasheet give information about a BJT's step response quality?

I did a test with randomly chosen 12 NPN BJTs. I applied a clock pulse to each of them and observed their collector voltages. Some of them showed very low rise time, while some responded terribly ...
2
votes
2answers
348 views

How do plasma lamps work? [closed]

I've been trying to understand how plasma lamps (or plasma globes, according to Wikipedia) work and why you don't die a horrible fiery death when you touch them. What I've got so far is that the ...
4
votes
1answer
4k views

Definition and Explanation of Insertion Loss and Return Loss

I'm trying to understand the physical meaning on Insertion Loss and Return Loss on a transformer, specifically RF transformers. The values are often quoted as figures of merit in datasheets, but I'm ...
0
votes
1answer
248 views

Where to salvage inductors?

I need a toroidal inductor for my ZVS flyback driver. The value should be between 47uH to 200uH. It should be able to handle 6A. Where can I salvage them from?
2
votes
3answers
571 views

NE555 Flyback Driver MOSFET failiure

simulate this circuit – Schematic created using CircuitLab I made this simple NE555 Flyback driver. I used a 9V Battery to power the NE555 and a 24V 6A power supply to power the flyback. ...
1
vote
2answers
188 views

How to amplify a 2MHz signal?

I am working on ultrasound sensors. At the receiving end I have a 2MHz signal of 80mV p-p. I need to amplify it at least by 10 times. Please suggest an appropriate method. Additionally, I need to ...
5
votes
2answers
1k views

Why does more bandwidth mean higher bit rate in digital transmission?

I understand that similar questions like this one have been asked before on this site, listed below. However, I am confused about the answers. If I explain what I think I understand, can somebody ...