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79 Threads found on edaboard.com: Measure Input Noise
Hi, I am trying to measure AC rms voltage using PIC microcontroller. I have attached the circuit for measurement. I am connecting a 3V step down transformer out to the input of the circuit.The feedback capacitor has been added to reduce the noise, but I am getting noise if I add this. This is getting (...)
Do as per FlapJack. We measure noise with 50 ohms system. Oscilloscope : 50 Ohms input, DC coupled, Offset adjusted. lower voltage/division capacity like 2mV or 3mV/div, try with 20 Mhz BW limit for better performance., Cable : RG174 cable(rf174-04sp3-04sp3-2000 these cables are avbl fom samtec) has very small core, useful in soldering (...)
I can understand RMS is like the average, not the instaneous value. but why sqaure it? why not just plain RMS. or to 3rd, 4th power. why square?
Hi, I'm having difficulty verifying my test for measuring noise Figure of an assembly using a spectrum analyzer set for noise spectral density. Essentially I'm trying to measure noise figure by loading the input to 50ohms, having the device on (with LOs) and measuring the NSD at the output. I can (...)
Hey all, I've done noise analysis on several signal paths now both measured with a spectrum analyzer and simulate in LTspice. I either measure or calculate the output noise in the units of nV/sqrt(Hz) and then refer it to the input by backing out the gain of the path. Only issue now is I'm working with (...)
How do you use a Wave Analyzer to measure Harmonic Distortion? What other kinds of test or measurements can you use a Wave Analyzer for? to do test or measurements for what kind of circuits?
you might be confusing different concepts. For example, to get a 1 Hz resolution, you need to measure for a 1 second time period for "normal" frequency counters. There have been some commercially manufactured frequency counters that had high frequency internal oscillators inside (500 MHz for example) and your input waveform gated the counting of
1) yes, so long as you do not overdrive the input with too much RF power 2) no, but you can measure the "residual" phase noise
Hello all! I am trying to perform some simulations on a TIA circuit on Cadence Virtuoso. In particular I am interested in plotting the BER vs input power graph, however I don't know any method to do so. For a particular input power I could measure the output swing it produces and divide it by the the output integrated (...)
I am using spectre to measure the noise performance of my schematic with spectre in Cadence . I wonder how the software to calculate the noise factor with the input noise and output noise . The simulation results show that noise factor doesn't equal to output (...)
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 (...)
Hi all Can I use the HP 8970B noise Figure Meter to measure the NF of an amplifier at 2-3MHz?
Just measure the noise at the output node of the device. If the device is in the middle of the circuit then you will have to measure the input noise and output noise, and subtract them to get the noise of the device.
IP2 and IP3 (input or output) are more related to the system design. As a stand alone device, for an LNA doing a simple P1dB measurement will give you information about the linearity of the device. Most of the time for LNAs is valid the rule: IP3(dBm) = P1dB + 10dB. To get this equation valid, the LNA should use proper bias filtering.
As said, I want to measure the input and output referred noise of an amplifier in practice. I have some thoughts and want to share them to see if they hold true. Assume a single ended input, single ended output amplifier. Should i do it like, 1) short the input 2) measure the (...)
Put a 10dB attenuator in between the oscillator and spectrum analyzer. Reduce the RBW to measure the harmonics reliable well above the noise floor. Check if the harmonics are still at the same level (~50dBc).
Hello all, I am designing a low noise amplifier for low power applications. I have a question. I know we usually use SP analysis to measure the performance of the LNA which tells us about gain, reverse isolation, input reflection etc. The problem is , I get different values of gain from noise analysis, ac analysis and (...)
I think the noise simulation doesn't need any input nor output sources in order to introduce/measure noise: you may remove I7, C0, V1, L1, IPRBB0 and L0 (which is a cap). Just refer the resultant output noise @ vo to the input noise @ the drain-to-source connection node, (...)
I have no idea, it is an ibm x60s, you say the dynamic range would not be enough to measure such things? Yes, by many orders of magnitude. The A/D chip in your computer's sound card is specified with 90dB dynamic range. Amendment: it seems that high qu
Hi everybodoy, I've got a doubt concerning the use of noise simulation in LTSpice. As far as I know, the input current noise density (inoise in LTspice) is the equivalent noise at input coming from every noise source in the circuit. I'm dealing with one schematic (...)
Greetings, In SPICE (like LTspice, Hspice) I can do .noise analysis and measure the total input-referenced noise using .MEAS noise in_totn INTEG V(inoise) How can I do the same in Spectre? I know that Spectre supports 'simulator lang=spice' and within this I can use the .meas (...)
If you measure V1 with a DVM, this will have a 10 megohm input impedance so the extra current, will be very low, and as you know its a 10 megohm resistor you can compensate for it in your calculations. Frank
The problem is only in that the noise sources and signal sources are available only as unsymmetrical, 50 or 75 Ohms. If you use such source to measure a symmetrical- input device, a balun or similar device is assumed to be necessary which has an insertion loss, to be added to the device parameters. To measure a (...)
Hi, dear all: I'm designing an ADC. I'm considering using correlated double sampling(CDS) technique. but if I use CDS as S/H, how can I measure the noise? (I input a sin wave to the ADC and did FFTin my previous design of common ADC, but now this method is not appropriate) thanks!
Hello all, I want to measure IIP3 and noise Figure with cadence application is a fully differential Low-Pass filter.Could somebody guide me with details how to setup the simulations?If possible i would appreciate a screenshot of a similar testbench for filter application. At the input of my testbench i use a port (port component fr
10MHz noise =100nV/√Hz 50nV/√Hz--> self noise 50nV/√Hz--> noise from LDO input after PSRR rejection Now I want to know how to convert 50nV/√Hz to the max ripple on LDO input Hi vovan, nV/√Hz is a spot noise measure, i.e. it states a (...)
DC Block That DC block has a frequency range of 10MHz - 12 GHz. The FSQ signal analyzer can measure down to 20 Hz.
1V is a bit low but it will still work. As the voltage you are measuring at the PIC input can't exceed the reference voltage, you are restricting the range of voltages you can measure and making it more prone to noise. What problem are you seeing at the moment? I use the AD584 as a reference when dead accuracy is needed. Brian.
thanks. how to measure input & output referred noise for a ADC
Hello all , how i can measure noise of a quadrature system refering it to single source at input and single source at output. Best Regards,
How did you measure these two eye diagrams, using a probe or direct connection from the laser driver to the scope input? Your (electrical) eye amplitude is very low, I wonder what extinction ratio you get in the optical eye? Post your schematic, so we can help better... Btw, I've done 2.5 and 5Gb/s laser drivers with far better eyes than y
SNR of what? & I guess you need to have signal generator & spectrum analyser in same box I mean synchronized, then only you can measure noise figure on SA & then you can calculate SNR.
Remember you cannot directly measure down to 0v. You really need to condition the signal first, say with a low noise op amp. Better to scale input so you measure say from 1-4 volts. You can the calibrate in software to give 0 to vmax output
hi every one, can any body tell me how to measure input referred noise of OTA in spectre. Thanks in advance.
How to measure input referred noise of an OTA in cadence. Thanks in advance.
we have the frone end, HP8970b. how do we measure it? anyone knows where to get the v band noise source or how to setup the ENR for 60G input?
You need two baluns, one at the input, the other one at the output and measure it in single end. Then apply Friis and deembed balun from measurement. I hope it can help. Mazz
It is common to measure (Carrier+noise)/noise figure at the demodulator input on a spectrum analyzer. All other figures we calculate from those experimental figure.
To measure the system noise figure the ratio of C/N measurement at output ans input are necessary. How to calculate the C/N at the output in a receiver after / before demodulation? Please suggest any alternative methods to find the NF accurately. I am interested to measure the system NF of around 1.5dB (...)
for a pipelined adc, how to measure its equivalent input referred noise in spectre? what maesures can be taken?and what is the approximate value of noise for a 10bit 15M sps adc? is there some advice and papers?thank all first.
Hi, I am designing a transmitter and I want to control jitter measurement by measuring noise on the input signal. Can I request anyone to please help and give me a code, as to how can I measure noise in the input signal for each clock period as I want to get Average voltage and RMS (...)
How to measure the input refferred noise in fully differential OTA? in hspice, who can give me a simple example? thanx
Hello, I want simulate my first first order delta sigma ADC, attached schematic. I can simulate it and I see behind the LP again my input signal. My problem is I cant see the noise shift to higher frequency. I simulate transient and adjust transient noise (noisefmin noisefmax and (...)
Hi all, I have a question. How to measure the SNR for the sigma-delta modulators. :?::?::?: Thanks in advance.
Using the Spectrum Analyzer (and a signal generator) you can measure only the Signal to noise Ratio at the input of the demodulator, which is given by the formula: SNR = 174 + RX_sens ? 10*LOG(BW_Hz) ? NF For QPSK SNR have to demodulate the signal and do a BER or EVM test.
Some basic questions? Which is the difference between the dynamic range and signal-to-noise ratio? What input signals are appropriate to measure these quantities? The dynamic range refers to current or voltage?
Hi can anyone guide me how to measure input refering noise by cadence ? My step is : - noise -> noise source -> Select node then - - simulation -> got to Result Browser -> frequency sweep -> innosise In calculator i don know how to give out input refering (...)
RX Level is not sensitivity. RX Level represents a signal at the input of your receiver. Could be anywhere into the range of the receiver?s dynamic range. RSSI (Read Signal Strength Indicator) could measure the RX Level.
noise figure is actually (i/p snr)/(o/p snr).....its ideal value is 1 although in practical, it is greater than 1..... when you try to measure the noise figure, you would optimize the circuit in such a way that maximum power gets transferred from i/p to o/p..... 50 ohm is just a standard in rf for terminating impedances.....although (...)
I want to design a comparator, the equivalent input noise of it must be less than 1/2 LSB of the syestem.But how can I measure the equivalent input noise exactly? Use the nosie summary of cadence, i can get a precise total output noise ,which will be constant when the stop frequency (...)