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Measure Input Impedance

149 Threads found on edaboard.com: Measure Input Impedance

True Large Signal Differential Input Impedance Evaluation

I want to measure differential mode input impedance of true large signal differential driving. Target frequency is around 1GHz. How can I do this task ? I don't mean conversion from large signal single-ended driving like following. {S11, S12, S21, S22} -> {Sdd, Sdc, Scd, Scc}

[Moved]: dark and illuminate current of a photo diode in a

Do you measure its output as current, or as voltage? To measure output as current, you need a loop of some kind for the current to flow around. It's likely that photodiode output is easier to measure as a voltage, instead of as a current. Photodiode schematics commonly show one terminal going to a high-impedance (...)

[ASK] Help me measure this graph

Hello everyone, I need help to learn the existing graph below : Figure 1 131529 Figure 2 131531 and what answer for this ?? 1. Why on the third draft of the array 4x1 has a different shape compared to the array of 2x1 or single element? 2. Why is t

measuring impedance using spectrum analyser

i do not have a network analyzer, but i want to measure the input impedance at one of the sma connectors of my ic(supposed to have seen 50 ohm). i have seen some post which can give a basic idea about the matching but they all require tracking generator but is there any other way by which i can see whether the impedance is (...)

problem with txline and manufacture of microstrips

Hi everyone! i have developed some microstrips, coupled mslines and cpwground with the software txline. my values for the parameter are: (here example for microstrip) Dielectric: RT/Durdoid 5880 (i have choose it for FR4 with dielectric constant 4.3) Conductor: copper impedance: 50 Ohm Frequenz: 2.87 GHz Height (dielektrikum):

How can one pracatically measure input/output impedance of a circuit?

also seeing that these are impedances and not resistances? Consider Z = R + jX In the general case, an impedance is comprised of a real (R) and a reactive (X) impedance part, forming a complex quantity. So what do you mean with "impedance not resistance"? Obviously a real impedance is easier to (...)

measuring energy of incoming pulse

measure the energy of the pulses. This could be voltage, or Amperage, or Watts. It's possible to get data by measuring voltage across a resistor which acts as a load for the incoming pulses. Is there a particular unit which you need for your readings?

How to Measure Tank Impedance of LC Tank in Cross Coupled CMOS Oscillator

Hello, I am designing a CMOS LC Cross Coupled Oscillator in ADS. How do I measure the Tank impedance in ADS - What testbench and set up would I use - would I just measure the input impedance using Zin. I also want to measure the Q of the tank as well to compare both to my hand (...)

How to measure the line impedance

Hello! I have a problem with finding out the impedance of a transmission line. Im working on a project and i need to find out a way how to calculate(find out) the impedance of a given line not using time domain reflectometry. What measurements i have to do to find out the impedance using only frequency domain? The (...)

Impedance measurement scheme

circa 70's-80's , I used to measure input impedance by using the scope X sweep out on the back to drive an FM input sweep generator then examine the envelope ratio on the scope for a linear frequency response. I got fancier by using X sweep out into Channel 1 then use CH1 Out on back of scope to FM input (...)

Can we measure floating voltage (of power supply) with reference to chassis ground?

Hi, read below "similar threads" In my eyes measuring this voltage makes no sense, because it is "floating". The voltage ins inpredictable an may change any time. (Caused by airflow, humidity, touching, connections of other floating devices...) Additionally the measurement device usually has a finite input impedance, so the (...)

Transmission Line Input Impedance by monitoring the voltage over the line

To measure the ratio of Z0 to Zi, the standing wave ratio on the line has sufficient information. But a slotted line can be also used to determine complex impedances by using the phase information. This has been in fact a state-of-the-art method of RF impedance measurements before vector network analyzers became available.

how to measure input impedance of gilbert mixer in cadence

If you don't have too much experience doing VNA differential measurements (and simulations), would be better to use a balun because you can choose the right impedance ratio of the balun, as in the list below from TDK: For using a simulator, TDK provides the S-pa

complex impedance covert to RL OR RC circuit

thanks for your input. i know how to calc them, but i want to use a VNA to measure some small rf compnents, so i need a tool. :) maybe i can built a simple program to calc them.

How to measure and obtain input impedance by R//C model

Hi all, Maybe you've found one input impedance of some RF or microwave device by the model of R//C,for example, the SAW filter is the most popular device in handset phone system and the input differential impedance of SAW filter is often the R//C or R//L model,such as 150Ω//82nH. My question is that how i can (...)

[CST MWS] How to Find input impedance of schottky diodes via simulation

Hi everyone, Can someone tell me the best way to simulate and measure the input impedance of a Schottky diode in CST MWS? It's an Avago HSMS-285X and a SkyWorks SMS7630 diode. The frequency range is commercial GSM/WLAN. Thanks,

Battery voltage divider to get hundreds of ?V levelse to measure ADC offset.

Hello. I'm trying to determine the offset of the ADC in my arduino Due, 3,3V reference 12bit SAR ADC. I can put on a small voltage without any transition from 0 reading but I want to know how little it is, 3300mV/4095=0,80586≈806?V LSB My brain does not literally work always as it should and today I can't figure out the simplest of thi

Return loss vs Gain level

The measure of good performance is good attenuation on the input reflection or in other words high Return Loss. Since it is loss a positive number is used. RL=15dB is generally considered minimum acceptable for simple circuits. impedance is geometric ratio of conductor width to gap to nearest grounds. Uniformity is key and matching (...)

HSPICE Software/Current Conveyor

I want to measure the input and output impedance (parasitics resistane at X, Y, Z port)of a current conveyor (CC-II) using HSPICE. Please tell me the method.

IC op amp input resistance or impedance measurement

Troubleshooting boards that are inoperative To test each stages IC inputs and output incircuit I tried using my Digital meter and set it to ohm to measure the IC op amps input The IC op amps input pins should be in the meg ohms from the the datasheets say for a 741 op amp out of circuit input (...)

Microcontroller ESD level 4 pin protection

I have been looking for a level 4 ESD pin protection on microcontroller pin( pic16f1503). The micro digital input pin is used to measure pulses between 50us to 200us. Do you think a circuit like this would work? R=500 ohms and C=0.01uF VESD=V0=15kv ( Level 4) Vc=V0(1-e^(-t/RC)) Ic=(V0/R)*e^(-t/RC) the RC filter will take 1.67uS t

Resistance/impedance measurement

Another possible solution.. If you know the components' values and part numbers, you can build the same circuit on a seperate PCB and measure it standalone. Then measure the input impedance of the circuit at the antenna input after that extract the s-parameters of the first copied circuit from these second (...)

Input imp. of diff. input stage using Port, RFlib balun and AnalogLib ideal_balun

I tried to measure the input impedance of differential input stage of mixer using s2p analysis in Cadence Spectre RF, I got same Z11 in following cases 1) When the Port connected deferentially 2) Using AnalogLib ideal_balun 3) Using RFlib balun (with Balanced output impedance set to 25 Ohms), (...)

Analog circuit design to measure pH value from sensor.

hi veeru you need make the circhuit with opamp to measure the PH output along with voltage offeset thanks

How to set the termination resistance of a GPS LNA power supply?

You can measure this impedance with a VNA by using a bias Tee.. Then you will have enough information what order of RF impedance should be terminated.

Measuring Input or Output Capacitance of a buffer

Hi i am trying to measure the input and output capacitance of a buffer stage (for example) as i need to measure several other stages i set up the following circuit 104476 and i set the input voltage to 1.2 with AC Magnitude and Amplitude to 1.2 , also vdd is set to 1.2 then i calculated Zin = I/1.2 * f howe

Gain changes in Low Voltage Amplifier over the time

Consider drift of 2% changes that affect output level and then verify by measurement. input level, temperature effects, R stability, measurement method

need help on OVP and OCP circuit

Hi Everyone, I am design a OVP and OCP circuit, and the input voltage is 3.7V~4.2V, max current is 3A. Here are some requirements: 1. The total impedance of the trace should be less than 0.1ohm. 2. OVP threshold is 6V and OCP threshold is 3A. 3. the OVP and OCP circuit can not draw current from the input rail since I will (...)

measure Zin of an cascode LNA from S parameters

I want to measure Zin of an cascode LNA using Cadence. I am wondering if this is correct. 1. measure S - parameters 2. Convert S to Z parameters 3. Zin = Z11 from the result above I know that Zin is not Z11 in ZP analysis, though.

convert frequency counter to Rf frequency counter

At 300mW you won't need any further amplification to measure the frequency. What is the input impedance of your frequency counter? It's probably a safe bet - and especially given its low working frequency - to assume it's high (...perhaps of order ~1Mohm?) The most important thing to be done for the measurement is to (...)

How to measure input impedence of an opamp?

Simulated "measurement" results aren't necessarily less accurate than datasheet specifications but hardly better. Everything depends on the model quality. Simulated measurements may be nevertheless meaningful to determine the effective input and output impedances of different amplifier circuits.

How do you measure the output impedance of an OTA in Cadence?

Hello All, Question is really in the title. I have a folded cascode single stage OTA. As there are cascodes on the output drivers I am concerned as to what the Rout of the OTA actually is. Does anyone have any suggestions as to the correct procedure to measure the output impedance of an OTA? As a suggestion, should I place a voltage

Input to ADC from a voltage divider

"Not correct" is somehow vague. What's the deviation? Is the ADC specified to measure downto zero? What's the required source impedance? Which processor?

ac vs dc analysis of a BJT

Thanks Frank. Every parameter in the sense , input impedance , output impedances can be measured ??? Also what is meant by Ft. that you mentioned in your reply Praneeth No - of course, impedances cannot be measured using dc analysis. With dc analyses you can only (...)

impedance matching for saw sensors ()

If this capacitor is series you should add an inductor in parallel.If it's parallel, you should add an inductor in series. Depends on capacitance configuration. But I'm not sure that the input impedance becomes purely capacitive.Because SAW filters generally have an input impedance with a real part by their nature. There (...)

Matching fet multiplier question.

yes I would match the input at F0 to get power into the fet. But I would also do something about presenting the right impedance to the gate at 2F0, 3F0..nF0 Similarly I would match S22 at NF0, but the question is: what impedance is optimal for that. it is NOT the S22 you would measure at small signal at nF0. Also, as (...)

The most plausible explanation is that your multimeter has about 10 MOhm input impedance, and you switched it between input and output. You need to connect an equivalent load instead of the multimeter to get the same input voltage when the multimeter is disconnected... To suggest a measurement trick: If (...)

How to calculate the input impedance?

In my opinion, it doesn't matter so much how you calculate or measure the input impedance as long as you tell how you did calculate/measure it: real circuits never are like an (ideal) VCVS nor VCCS - mostly something in between, and they mostly have defined loads. In a real circuit I'd want to know the (...)

high input range amplifier

The bottom limit is defined by noise. If you measure a DC voltage, check the opamp 1/f noise and use a low-pass filter to limit noise bandwidth. You also have to define the input impedance to refer the noise power and voltage. The higher the imedance, the higher the noise level. If you refer to audio frequency range, then there are many mV (...)

opamp feedback calculation

I would look on the "floating battery" point from the other side. A differential amplifier with finite common mode input impedance has no problems to measure a floating voltage. A floating voltage will be "pulled" to the amplifier ground by the input impedance. But the battery is unlikely to be floating (...)

Neither one.. When you do s-parameter simulation, you should terminate each port with PORT element to able to measure input and output impedances and the Gain.

Calculation of PULLING resistance for PULL-UP and PULL-DOWN Bidirectional I/O PAD cel

bidirectional pull-up(PDU02DGZ from tsmc) and pull-down(PDD02DGZ from tsmc) cells. Help me how to simulate for pulling resistance. I/O pad cells' output always can be disabled (OEN=1 , input state is irrelevant). Run a DC analysis and measure the output impedance.

how to measure input impedance of a power detector (diode detector) circuit

Hi all, I got zero bias shottky diode based power detector. It gives DC output upto -30 dBm power input. I want to measure input impedance of this circuit. I just connected the input of the circuit to VNA port 1; it shows about -3 dB in magnitude plot. 1. Is the method I used to (...)

Impedance measurement using I/Q demodulation

Hello! I want to measure an unknown impedance using an I/Q demodulator. Setup: I was thinking of using a DDS (Direct Digital Synthesizer) as the sine wave signal generator. Splitting this signal to a reference signal and an excitation signal. The reference signal will go directly to the LO input while the excitation signal will go (...)

HS1101 humidity sensor

We've already established that the ADC input is not high impedance. Maybe another approach would be to apply a square wave to the RC, and measure the peak output voltage, since it would essentially be a low pass filter.

Using high resistor values will give you wrong results due to the slow charge rate of the S&H capacitor but if the signal you measure is not a rapidly changing one you can use a capacitor at the ADC input that can act as a reserve and present a low impedance to the ADC input It is also a good idea to use Schottky diodes (...)

50 ohm antenna matching

To be able to measure various impedances, there is a general concensus to use 50 Ohms for signal sources, transmission lines and loads. In your case the receiver input may be matched (i.e. having the impedance of ) 50 Ohms as well as the antenna. Antenna impedance often differs (due to conductive objects in (...)

S-parameter measurements

The RF input power for the transistor (or the output from network analyser) is indeed 0dBm. Do I need any higher value for S-parameter measurement? 0 dBm is 0.77 V into a 50 Ohm load, and up to 1.54 V into a high impedance load. You should measure with less power.

Accurately measure voltages across loop antennas

I would measure using the usual instruments (network analyzer or signal generator + spectrum analyzer/power meter) with some high impedance (kOhm) voltage divider at the loop antenna. This gives you (relatively) high impedance to measure the voltage. Calculating the attenuation caused by the voltage divider to the 50 ohm (...)

how to determine RF receiver input impedance

Use a VNA to measure the input impedance and design a matching network. Or at that frequency you can rely on the fet device model from the manufacturer.