High frequency Definition and 87 Threads

What is the best way to generate a signal with a high frequency (700 MHz - 30 GHz)? Is there a preferred circuit diagram for such a design, or is it better to use a processor of some kind? Is it really heavily based on the length of the antenna (dipole)? I am trying to do it as cheap as...

I need a transformer with the following characteristics that can operate at a frequency of 1MHz. Step-up ratio= 1:80 Primary L=1.55uH Secondary L=10.65mH Mutual Inductance= 62.5uH Any suggestions on what US companies might carry this kind of product?

Hi. I noticed that my phone charger (output: 5V DC) makes a constant high pitched noise when plugged into the wall. It's not too loud but you can hear it when you are within maybe 4 ft of the charger. When I plug my phone in, it starts making intermittent noises. I was wondering what this could...

Sky waves transmission is done using the total internal reflection phenomena. The waves reflect as we go to a rarer medium from a denser medium. My book states that high frequency waves cannot be used for sky waves. IT says it will penetrate the atmosphere. I don't get it refractive index...

Hi All, Currently Iam working on a project where I have to superimpose High frequency component on AC mains 240V 60HZ. ( Its imposing Ripples in mains voltage... as happens when voltage is generated from a Petrol generator). Need some help how would i do this ? Thanks in advance. Shakey...

I have a project about High Frequency Dielectrics and I am searching everywhere but nothing found. Please I need your help to find some information that would help me in my project.

Homework Statement An MOS device has a following high-frequency C-V curve. The oxide thickness is 15nm. THe silicon doping is 3x10^17 cm^-3. Neglect interface charge. a) drawt the band diagram (include the gate electrode and gate oxide, label Fermi levels) at bias point where Vg=0 (point...

Hey guys, I'm designing a wireless charging system, and I've managed to take some measurements between two coils for the voltage transfer, but the signal generator I'm using doesn't seem to output any measurable current. What could I do to it, or what could I design from scratch that...

Hello, I am hoping someone can break down an equation for me. I am used to Kirchhoff's law in the form of i1 + i2 + i3 = 0 etc. But recently in a High Frequency class, we were told ...'Let us apply the Kirchhoff's law to the equivalent circuit of a transmission line segment of length \deltaz...

Hello everyone, i have a 312MHz square wave oscillator and want to generate a 312MHz sinewave with it.i googled it but did not get much info,if anyone can provide some information on how to proceed or any ic capable of it,that would be of much help to me. Thank you

Hi i wonder if the diode I-V characteristics will be as usual at it is operated at high frequency? Some one told me that it will be not the same. There will be a some kind of hysteresis loop will appear in the curve. Can anyone ensure me about that or give me a useful link about that topics?

i have been working on generating high frequency alternating magnetic field (amf) generator (100-500 khz range) to magnetize magnetic nanoparticles contained in a plastic test-tube wound with copper wires around which amf has to be generated. what is the best option to choose for such an...

Can someone explain me what do high frequency semiconductor devoices mean? how to differentiate between low and high frequency devices? Thanks

As is commonly known metals are good mirrors i.e. they reflect very well visible light. I wonder whetehr is it true for frequency much higher then the frequancy of visible light. Does exists the frequency for which metals are almost transparent?

Ive read on loads on places that tell me this but don't explain why. They explain the closed loop gain drops off because the open loop gain in their 'real' equations is no longer infinite/very high so the assumpstions that lead to ideal equations fail. but nowhere can I find an explanation...

Hi, was just wondering if anyone could help me out with this query, I'm just curious to know why high frequency acoustic waves are greatly absorbed underwater? Thanks in advance.

I watched on 60 Minutes: How Speed Traders Are Changing Wall Street I heard about "high frequency trading" before, but don't know how useful they are, and what are the risks to the economic system, and to the average investor. I know a lot of people have suspicions about the people using...

Why use high frequency power supply for generating plasma?? Hi everyone, I noticed that for the plasma ball common in science museum, power with high frequency should be used for generating so called plasma inside to give out colorful glow. But one thing I can't understand is why power supply...

Hi, I found something quite interesting about resistance in my book. It says that at high frequency (MHz scale), resistance R decreases due to "inductance L" and "capacitance C" characteristics of resistor. So the resistor can be modeled as (Ro in series with L) // C (Ro denote the resistance...

Hi, I am required to design a monostable multi-vibrator suited for high frequency 200MHz. I am currently referring to this site http://www.play-hookey.com/digital/experiments/rtl_monostable.html for my design, however, it seems that this is only made for low frequencies. What should I do in...

I need a solution to the question, Which clamp-around-the-cable ammeter (digital or analog) can be trusted in measurement of current draw by a high-frequency AC tig welder? High-frequency AC is a requirement of welding aluminum, and an electrician measured 150+ amps at full power welding...

Hello everyone, I'm new here. :smile: Because I feed wild birds in my garden, my neighbour has mounted an electronic bird scaring device on the outside corner of her bedroom windowsill angled so that it is pointing directly over my fence into my garden. :mad: This device is meant to be an...

How small can I make a transformer and still get 1:30 or preferably higher step-up ratio ? I have been reading a lot about transformers and I know using higher frequency will reduce the size, and I need to use ferrite core for high frequency. I don't want to use really high frequency, probably...

Hi, We would like to connect an amplifier to produce the appropriate alternative current for a high frequency actuating system. Who here knows where I can find an opamp with the following charachtristics: 1) Non-inverting 2) Amplifies an alternating input current 3 to 5 times 3) Works...

Ok topic was rather unscientific i know, but yes, i want to know, what are the highest frequency waves that are laboratory producable? also, what are the limiting factors in designing devices capable of reaching upwards of the YoctoHertz range for example. how are the frequencies generated in...

Hi, I'm trying to build a high frequency generator. The pulse needs to have atleast 1ns rise/fall time, variable amplitude (~0-8V), 50 Ohm output impedance, and have very little jitter/be stable and I need to be able to set the pulse width and delay from ~5-1000ns. Cheers, Steve

Hi, recent EE graduate, I'm working on a project for myself. I dealt with mostly controls, signals, and digital stuff, and not enough electromagnetics or RF so I am pretty clueless here. If I were to radiate the full electromagnetic spectrum from dc to visible light onto a copper cable...

HF HV to LF? I wanted to say that I have searched the site and it is very imformative, glad to be apart of it. That being said I had a question, what means would you use to convert high frequency currents to that of line current(60hz)?? I have searched and searched on google and have not...

Hihi, I don't understand what is the meaning that BNC cable transfer high frequency signal? For example, I use BNC cable for the connection between my diode controller to the diode laser. I also use BNC cable to connect my photodiode to the oscilloscope. I'm not sure what is the...

Why can a sound wave with a high frequency travel further and stay more concentrated (i guess there are basically the same) than one with a lower frequency? Thanks.

Hi All I would like to build a synchronous detection circuit for detecting the real and imaginary part of the signal (I and Q value), the operating frequency for the system is 20 MHz...I would like to know is there any existing chip that can generate the quadrature signal for me (cos wave and...

Dear colleagues, I have a question related with dielectrics and their conductivity when High Frequency signals are applied. Is it possible to become conductive a dielectric material if sufficiently High Frequency signals are applied? When a high frequency signal is applied to a...

Hi, When you have a high frequency high power alternating current, Can you use a regular wire to transmit the current or do you have to use a waveguide? Or some kind of combination? Thanks.

I've heard that if you pass a high frequency AC (26kHz?) current through water it boils. Does anyone know if there is any truth to this? Has anyone ever done it?

Why is it that higher frequency states in the quantum ideal gas get less energy than what is predicted by the equipartition theorem? I understand the argument about low frequency states. They do get the same energy..all of them. But high frequency states do not have the same agreement...

Why is it that higher frequency states in the quantum ideal gas get less energy than what is predicted by the equipartition theorem? I understand the argument about low frequency states. They do get the same energy..all of them. But high frequency states do not have the same agreement...

Is it possible to make very small, low power, but high frequency electromagnets and stack them up or inside each other to make a high field strength, high frequency magnet? or does the presece of other magnetic fields cause the same problems you would expect with only one coil?