Rf Definition and 254 Threads

i am trying to design a robot which can track a transmitter which produces rf signals in a given range of frequencies(example:- 400-900 MHz). i want to know the following details. 1. i have a design of wireless robot with A433MHz RF modules. i need to change the frequency of transmission...

I got a dirty electricity problem from a smart meter There is supposedly filters on the market that remove the incoming RF frequencies and puts them onto the neutral. Does anyone know how a capacitor plugged in would remove RF frequencies from the hot wire and send them back on the...

I need to design a class D low power RF amp that I can control the RF output of without tampering with the input signal. I need about 200mW out @ 50 MHz but the input drive is a digital coded pulse train I can't tamper with in any way. I need class D for best efficiency and battery life. How...

Even though their molecular formulas are the same? Fructose is an isomer of glucose and they are both cyclic and have 5 carbons so I was wondering why fructose was higher on the TLC plate than glucose. Thank you.

I'm trying to determine the best method of measuring impedance from a wire through it's glass coating to determine if the thickness of the coating is correct. At the moment I do not have the actual frequency, I just know it is in the RF range and that my impedance needs to be 50 ohms. I've...

What is Rf --> Op_Amp 1. Consider the amplifier circuit shown. What value of Rf will yield vout = 2V when Is = 10 mA and Ry = 2Rx = 500Ω 2. The way I did this was by employing KCL: (Is that applicable?) The Attempt at a Solution Rx(Is) + Rf(Is) = Vout I'm actually not quite...

Hi all Sorry if this is quite a basic concept, but I am confused about RF signals. The way I currently understand it is that radio waves in space are an oscillating electric and magnetic field at 90 degrees to each other traveling through a medium. However, when you pass a radio wave into a...

Can anyone tell me what a high gradient RF structure is? I think it is referring to the strength of say an electric field in a structure oscillating at radio frequency but I am not sure. I would appreciate any explanation.

I'm trying to get a basic understanding of RF DAC. If I have a DAC that does 100 MS/s with an 8 bit resolution, this translates to a 800 Mbps throughput. Or is this too simple? Now, how does the bandwith of a channel affect this? Say I have two 5 MHz channels. With two channels there...

Hi everyone. I was wondering how badly aluminum affects RFID waves (860-960MHz)? Do they completely absorb, reflect, combination of the two? I'm having issues with my testing of RFID. I'm getting some dead zones and I think it could be because of the portal frame the antennas are mounted on...

Please guide me how to prepare for interviews for the post of RF engineer and/or DSP engineer. I finished my masters in electrical engineering and am looking for a job in these two fields. Topics and concepts that I must prepare and also the practical skills one must possesses (I have...

I read that conventional (low frequency) circuit parameters - voltage gain and power gain are not applicable for RF circuits but I didn't understand why? Can anyone please explain.

Why isn't it possible to invent a custom digital modulation scheme that would use much less RF bandwidth than all the schemes available? What are the limiting factors that do not allow for high data rates to be coded so that the occupied bandwidth is much less than all the others like ASK, PSK...

I have such MATLAB problem: I create variables R1 RF R2 and w so: Code: syms RF R1 R2 w then I write expression: Code: 3*R1*w*(RF + 200)/((R2*w*29*i + 3)*(3*R1*w - 2*i)) which gives: Code: (3*R1*w*(RF + 200))/((3*R1*w - 2*sqrt(-1))*(R2*w*29*sqrt(-1) + 3)) why sqrt(-1) and not i...

I've found out very quickly that I can't use a breadboard for RF circuits, what is another choice? I know PCB's would be best but making them is very tedious for me. I'm new at this stuff so I plan on experimenting quite a bit which is another reason I want something quick and easy to replace...

As title. Thank you. In the context of MRI, why/how does applying 90 degree radiofrequency at Lamour frequency put proton precessions into phase? I understand 90 degree RF minimises net magnetic moment, such that there is least difference between number of protons in parallel (with...

Greetings, PF'ers I've got a project where I'm trying to measure the distance from a stationary AM radio beacon transmitting a short coded pulse every 300ms or so to a non-stationary receiver. I'm dealing with a range of about 1 to 500 ft between points. I need to have at least 1'' accuracy...

RF question -- Plane radio aliasing? I hope this is the right place to post it. My buddy and I were working on a jet earlier and turned on the HF communication system to perform an operational check out of the system. We tuned the radio to 2.5 MHz and picked up a local AM radio station. The...

I have been reading about RF power and equipment. Can someone explain to me, in very simple language, how it works. I know that RF is a frequency range, and the amplifier obviously amplifies the power. Can you explain the coupling network, and how RF power is generated. Baisically the process of...

I've designed both types of filters for years and can't really explain the difference in clear simple terms. I'm hoping somebody here can help me out with that. First, some working terminology: RF filter - a filter with a controlled input and output impedance, usually 50 ohms, to match the...

I am trying to design a system to measure the distance between two RF transceivers with as small of a resolution as possible. Time-of-flight measurement is nice and easy to do, but it has a poor resolution with low frequency timers. I am thinking of using a low-cost mcu that will probably have a...

Hello all, I'm not sure if any of you have ever used a device that measures RF transmission line loss and presents it as a graph of Insertion Loss (dB) vs. Frequency (GHz), but that is exactly what I'm trying to calculate. I've been looking through equations for days, and I just don't...

The program I am looking at has an emphasis on Electromagnetics, RF and Microwaves. If I am looking at the telecommunications industry, what other exposure might be valuable? Would some course work in Signal processing or embedded systems be beneficial?

Hello. Yangman here. I come here write an advice. Do not study digital field in EE. Every day I meet some digital circuit chump who call himself engineer because he understand AND NOR NAND NOR and verilog. Just because you can make LED blink on Arduino do not make you real engineer. I give...

I am quite inexperienced with actually using mixers, so when I was bombarded with specifications by a data sheet I was a bit intimidated at first. I think I have learned what most of the metrics mean thanks to a great deal of resources available online. I just have one question. The data sheet...

I made a DIY RF trasformer, and I want to know how much RF power can it handle, I want it to work from 500K hz to 3Ghz, have DC resistance 0.1ohm, L primary=5nH. There would be no DC current through this part. How would I know how much RF power my part handles? Do I send a voltage through the...

I was looking at the MS (non-thesis) in EE with a focus in Electromagnetics, RF and Microwaves. I realize jobs in military and commercial sector for communications, radar, etc. What else is out there? What kind of security would this degree offer me?

My take on RF in electronic design has always been, if the wavelength of the frequency you are working with is less than 10 times the length of the board/device(s), you should be using impedance matched networks for traces and cabling. Currently I have a problem where the wavelength is the...

Hi Australian citizens/ expats living in Australia What are some companies in Australia (including international companies that have Australian offices) that manufacture and produce Radio Frequency equipment ? I have a degree in RF engineering, but getting a f/t job in the area is...

Hi Folks, I didn't know exactly where to put this post, so if it's in the wrong section, I apologize. On to it then. I'm in my final year in EE, and I want to work on a project that let's me become comfortable with RF/Communications concepts commonly run into in industry. I was...

I just started learning about Op-Amps. Working through basic equations seems straightforward, however I was curious about the function of the feedback resistor. As the name implies, one might infer the current/voltage potential "feeds back" from the output back into the input (I know there are...

Hey all! I have just constructed a RF circuit to try out. I made use of the T5-434-5V and the R5-434-5-128 transmitter and receiver pair and also the HT12E and HT12D as the encoder and decoder for the transmitter and receiver respectively. The schemetic I used can be found on page 6 of this...

What is the easiest, cheapest what to increase the range of this RF transmitter? Right now it outputs 8mW which gives it about a 500 foot range. I need it to be increased to about 40 miles line-of-sight. http://www.sparkfun.com/products/8946

I'm having to re-learn RF design after years of not doing it. Can someone lead me in the right direction? If I have two RF networks, say two simple LC filters and I need to feed them both in parallel with the same source simultaneously, what are the steps? To make it easy, say each filter is...

I would like to ask a few questions. Does a table of refractive indices of materials at rf frequencies (say for TV) exists? Is there a way for me to estimate it for some materials? Are the refractive indices of these materials higher? Will those materials have low absorption losses at these...

I believe its possbile but wanted to ask if its possible to light a single LED light by and RF signal if its strong enough. I know there are LED's that are as low as 3 milliwatt that could work. Thanks in advance.

Dear Experts, I am looking for some rf vhf diodes. could you recommend a particular model for me? I am quite new to this diode. Are these synonymously called microwave diode / MOSFET / rectifiers / field effect transistor? I am confused what should be the right diode to amplify gsm...

Question is simple: Automatic vs RF engineering in future? And if you can tell some of precise jobs about any option. For example, I heard that, if you want to work in oil industry (on rigs etc.), automattics are way better option... Specific advantages about RF still not sure... (I know it's...

Can anyone tell me where I can find a basic T parameter table for RF design. One with the T parameters for shunt impedence in coaxial, series capacitance in coaxial, coaxial of length l etc...

Hi there, I noticed another thread about a guy who was considering living near a cell phone tower. People pointed out that he shouldn't worry because the amount of watts was low compared to tv towers etc. This makes me worry because I'm going to be moving into a property about 200 metres away...

Hi to every one I want to simulate Rf lab plasma and DC glow discharge plasma But let me make clear one thing Consider me as a starter to both plasma physics and simulation So is there anyone who can help me in this respect to guide me from zero Regards

Hi, I'm interested about situation in radio frequency engineering. Is there difficult to find a job in this profssion and what jobs exactly RF engineers do? Thanks.

Hello I have a basic question about the decibel -voltage - watt conversion. I am calculating pulsed RF power on the scope. The setup involved an RF transmitter connected to one end of an attenuator. The other end is connected to the scope. Sure I used 100 dB attenuator first and decreased...

I've picked up a 13.56 MHz RF generator from eBay which I plan to use for an ICP plasma project (this is what it was designed for). I need to construct an RF coil and parallel capacitor with a resonant frequency of 13.56 MHz but I also need to construct an AMU as, as I understand it, as soon...

The basic premises of what I am trying to do, is build a transmitter receiver circuit that has a signal strength identifier so I can calculate the distance between the transmitter and receiver. For example, if the chip is receiving 100% of signal strength (2mW) the distance equals 40 feet, and...

what is the meaning of Video bandwidh for rf detector?

I have a question about making an LED light up when sensing audio. Right now, I'm using Super-Regenerative receivers and testing various components of them. Using a signal generator, my audio speaker squeals, as it should, when on the right frequency. When it's not on the right frequency, I hear...

it seems like looking at beam patterns from directional RF antennas the beamwidith is something like inversely proportional to the parabolic reflector diameter. why can you make an almost perfect strait parallel beam of light but not with RF?

I'm considering taking an RF circuit design class that would focus heavily on transmission lines and microwave circuits. It's supposed to be a tough class but I think I would enjoy it because I really like E&M. The problem is that if I take this class I won't be able to take a photonics class...

Hello all, I'm now working on the 2.45GHz frequency transmission line layout on the PCB. I would like to know whether there is a design guideline for the 1) minimum length of the transmission line. how do I know or calculate? I can calculate the width of the TL to get the 50ohm impedance...