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

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57 views

Can anyone recommend me a Microcontroller for this purpose? [closed]

I recently began looking into the world of Micro-controllers, ARM things, "Maker" things, but, that world is so diverse, I cannot even begin to choose from all the Micro-controller galore I've seen, ...
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0answers
55 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
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1answer
39 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
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1answer
55 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 ...
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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 ...
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0answers
43 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
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1answer
84 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 ...
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1answer
72 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 ...
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1answer
124 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 ...
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2answers
73 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
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2answers
170 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
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2answers
68 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 ...
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0answers
125 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 ...
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2answers
144 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 ...
0
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1answer
93 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? ...
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1answer
94 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 ...
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0answers
52 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 ...
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2answers
61 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 ...
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2answers
419 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 ...
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1answer
84 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 ...
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2answers
136 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 ...
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2answers
275 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? ...
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5answers
1k 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 ...
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0answers
21 views

Noise in Inductor Current : Buck Converter [duplicate]

Source DC: 300v DC Output DC required : 160v DC Load Current : 7A DC Buck Converter Topology : IGBT as switch @ 8khz 1.1 mH Ferrite Core Inductor Measured Inductor Current ...
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3answers
106 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 ...
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1answer
213 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 ...
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2answers
257 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 ...
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1answer
190 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 ...
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4answers
805 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
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1answer
297 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 ...
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5answers
393 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 ...
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2answers
173 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 ...
3
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1answer
2k 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 ...
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1answer
195 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?
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3answers
403 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. ...
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2answers
140 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 ...
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0answers
51 views

Minimum Distance for Corner Reflector

In RF-Measurements Trihedral corner refelctors are often used as calibration targets because of their constant and analytically defined radar cross section. The RCS of a trihedral corner reflector ...
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2answers
762 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 ...
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2answers
265 views

Minimal distortion in transmission line

In a transmission line, the condition for minimal distortion (caused by the line) are when (R/L = G/C) in the line, right? However, I don't see any reference to that in any application notes or ...
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1answer
184 views

IC555 flyback driver troubleshooting

I made a flyback driver which just uses an astable 555 circuit to drive the flyback. The 4 and the 8 pins were connected to the positive rail. 7 pin was connected to the positive rail via a 1K ...
4
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1answer
161 views

How can I track where this 471kHz noise is coming from?

I'm new to EE in general and I just received my first oscilloscope (Rigol DS1102E). Anyway, I'm building an audio circuit using an Arduino Micro and the infamous ...
0
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1answer
256 views

How to make prototype circuits that include microcontrollers, and avoid breadboard annoyances at high frequencies?

From my searches of the web ( as well as this question ), I have found that breadboards - like the one on picture - aren't a good idea when your application involves high frequencies. I am going to ...
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1answer
209 views

How to design a 1-500MHz sine wave level detector to -90dBm?

I want to build a sine wave level detector that works for a single 1-500MHz sine wave in the range of -40dBm to -90dBm. This is a hobby project - so cost is not a big obstacle :-), but I want to stay ...
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2answers
2k views

Can anyone explain this high-frequency “alien voodoo black magic”?

I was casually watching Mike tear down a spectrum analyser (13:30 is the relevant part, 16:50 is the awesome part), and he came across what he aptly described as "weird messed up alien voodoo black ...
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2answers
624 views

How does an increase in operating frequency result in decrease in the size of an inverter circuit?

I was reading about inverters in a textbook where the author says that The size and cost of the circuit can be reduced to some extent if the operating frequency is increased but then inverter ...
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2answers
145 views

Describe qualitatively the amount of current passing through resistor if the source oscillated at low frequency?

I am stuck on lab question 3. I do not know how to determine the current crossing the resistor for oscillating current at varying frequencies. Help is greatly appreciated
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1answer
103 views

Looking for High Speed Parallel DAC IC without data latch

I have designed a FPGA based DDS that creates digital signals between 0-70MHz. Now I want to convert my digital data into analog. As the base frequency is 200MHz, I need a high performance parallel ...
2
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1answer
171 views

High voltage, high frequency, pulser

For a rather unusual application, I need to generate high voltage (>500V) pulses with a very short rise time (10-100ps). Is there something that can do this off-the-shelf? Assume money is no object. ...
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1answer
172 views

Confusion regarding considering a transmission line as lumped or distributed

I am just elaborating my question. I have came across different formula's to say whether a Transmission line is lumped or distributed. in one of the books i read " Effective length of a electrical ...
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2answers
210 views

USB Full Speed driver with MCU in DIP package

I desire to apply a USB driver with a MCU that has a DIP package. The device should communicate in Full Speed (12 Mbps). To your experience, is that possible? Taking into consideration the physical ...