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Quarter Wavelength

1000 Threads found on edaboard.com: Quarter Wavelength

Seeing a crisp rectangular wave on an oscilloscope

There's probe bandwidth and there's channel bandwidth. Probe BW is lower as far as I've seen (because what's the use of more BW than the 'scope front end can pass?). 500pS risetime is (if you call it a quarter cycle) 500MHz (-ish) and you can find passive probes of about this range. The idea of using 50-ohm cable and a well constructed p

I need more ideas on underwater transmitter and receiver circuit designs

I want to design an underwater optical communication system with high speed and bandwidth to show the effects of absorption, scattering and turbulence. I need ideas on the circuit design for the transmitter and receiver. I would also need to simulate it on Optisystem and Matlab. I need ideas on how to simulate the processes on these programs. Thank

Implementation of sine cosine using LUT

I know the "quarter wave" LUT implementation.... but quarter wave means 4 x 90°. How does the 45° table work? quarter wave is 90 degree, thus 32 points per 90 degree. 45 degree table makes no sense for sine LUT. Interpolation error with 32 point table is already very small. There's no application mentioned in this thread, thus

12v DC proximity detector for use on truck (2-3 feet range)

Hello. Well after the 3rd time getting hit at work, this last time was major damage... of course no one said anything. I suspect that the issue is parking. The parking lot is a crappy design. Anyways, I built a bull bar for the rear bumper (its a truck) but I need some type of proximity device that will cover the sides. Especially the rear quarter

Two patch antennas gain

Hello all, I have a question regarding two patch antenna array. does the distance between the patches varies the gain? (they are separated with at least lambda/2 so neglect coupling) I think that it does not, since the far field is composed of two elements: 1. Element pattern - does not change 2. Array factor - does not change at the max sinc

forward voltage of LED diode

I found all the LED diode have a minimal forward voltage of 1.7V. Anyone knows that whether there are some LED diode with forward voltage less than 1V, and the forward current is less than 20mA? Thank you.

Why is CO2 a green house gas? [CLOSED]

What happens when a CO2 gas molecule in the atmosphere absorbs a photon of infrared radiation which has been emitted by the Earth?s surface? What about photons that are coming in from the Sun? As far as I can see, incoming photos would also collide with some of the CO2 molecules. So why does more heat come in than goes out? Any assist

RFID Coil design and Simulation

hi I need some design application notes for RFID coils. Can i simulate coil in ADS or HFSS etc. Is there any example available for ADS momentum. Is it possible to beam forming using coil arrays? Regards

Design and construction of a system identifying N2 nad H2O

I have read papers that use LIDAR-like and LIDAR-Raman systems that detect elements. I want to measure the vapor water (H2O) and N2 of trees/agriculture using Arduino and low cost elements (DIY). I am thinking of using 405 nm 500 mW laser. The problem is how can I detect the returned wavelength? What I am thinking: 1) A CCD sensor? 2)

Thermal camera reading fet temperatures...how far away to hold it?

For assessing the temperature of FETs on the PCB, how far away from the fet should this thermal camera (HT-04) be held? The spec appears to suggest 32 inches away? We do notice that the temperature reading varies as we move the camera nearer/further from the fet.

Deriving admittance matrix for shortened quarter-wavelength transmission line

For Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's , how to derive equation (2) ? and is the imaginary constant j needed in equation (1)

Extend life of UV lamp.

Any tips and/or info on how to extend life of UV lamp. Thanks in advance.

Strategy for a multi signal generator using a MAX10

As mentioned by betwixt, always link related threads 1. I tried, it works, it makes a sine wave from a quarter of a sine wave, but no internal RAM is used, RAM Can't be used, apparently. Partial RAM tables (e.g. quarter wave) can be used,

ABCD Matrix of transmission lines connected in cascade

Hello, I need verification of problem which I analyzed yersterday. Let we say, that we have simple circuit composed of transmission lines: 154760154760 As you can see, we have one simple quarter-wave TL, and two open-ended stubs at the end. I want to derive an ABCD matrix of entire circuit in e

Wire to RF toroidal coils?

To factor in only skin effect will underestimate the AC resistance, there's also proximity effect. Respectively, parallel connection of 4 wires will hardly achieve quarter resistance. Study the stranding scheme of litz wire to understand what's optimal. For low number of strands, twisting is O.K.

Doherty Power Amplifier

How to determine the impedance at combining node (Rcn) of doherty sub-amplifiers? Is it a standard for all DPA designs? Or depends on the design? Thanks in advanced154540 This is the standard Doherty impedance that you see. Rp=Rl' / (1 + I_carrier'/I_peaking) Where I_carrier' is the current

Design a driver for DFB laser

Hello I want to design a drive for a DFB laser transmitter. I want guidance for circuit design. And whether you have micro-code source code?

Generating a frequncy

Helo all.i need a circuit which can generate a frequency of 27Mhz having a pulse rate of 800 pulses per second."Pulse on duration" should 100 micro seconds.Any one have any idea about the implementation of cicuit?Antena size should be 8cm

Power amplifier impedance matching

You can with multiple transmission line stubs. Obviously not all exactly quarter wave length. Smith chart tools like SimSmith will help you to design the matching network. As a simple approach (not necessarily the best), use one shunt stub at each side to compensate the imaginary impedance and a quarter wave series line to match the remaining re