# Questions tagged [signal-to-noise]

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32 views

### Problem in deriving Noise Figure for Cascaded systems

I am trying to derive Noise Figure of Cascaded System. I am making some conceptual mistake somewhere in derivation and getting wrong answer. Can any one please help me figure out where I am going ...
63 views

### Avoiding signal interference in a cable that carries video signal and sensor signal

I am using a 6 core shielded cable. In this 3 wires are used for a sensor and 3+1(shield) is used for a analog camera. All the cores take DC supply. Sensor(3 wires) (+)24 volt supply, (-)minus, ...
19 views

### How does electrical noise affects signal and distribution power?

What is electrical noise and mechanical noise How does it interfere with power? - signal power - Power distribution/ transmission
23 views

### How conventional DFE (Decision Feedback Equalizer) works?

There are a lot of variations of DFEs online. But I couldn't find a step by step explanation on how for example the 2-tap DFE works. Can you provide an explanation with a scheme ? I looked for some ...
42 views

### SQNR and Dynamic Range

An audio tone $Acos(\omega t + \theta)$ undergoes uniform quantization by a quantizer that has the average quantization noise power $q^2/6$ joules, where $q$ is the quantization step size. If ...
127 views

### Harmonic detection using lock-in amplifier

Can a third harmonic of a signal be detected using a lock-in amplifier under the same parameters fixed for collecting the fundamental or the parameters needs to be adjusted.Here by parameters I mean ...
38 views

### Communication in presence of noise: Why is the number of distinguishable amplitudes K*sqrt((S+N)/N)

In section VII: The Capacity of a channel in the presence of white thermal noise in his 1949 paper Communication in the presence of noise, C.E.Shannon says, that for a signal with average power P, ...
131 views

### Signal noise cancelled by touching the leads

I have a pressure sensor that outputs 0.5V with a +/- 20 mV noise. I am trying to identify the root cause of the noise using an oscilloscope. The noise occurs in waves of twice the mains frequency, ...
52 views

### How to use my bits to transmit this photodiode signal in the most efficient way possible? [closed]

Suppose I have photodiode with a Dark Current of 5 pA and that using the NEP of that photodiode at some frequency $\lambda$ I determined that the smallest signal I could detect was of 1 pA. First ...
75 views

### Estimate minimum detectable light pulse in a photodiode (5 ms, 44 kHz modulated)?

I'll use an IR LED modulated at 44 kHz to illuminate particles in air or water, and will use a silicon photodiode to detect weak pulses of scattered light as they pass through the LED's collimated ...
38 views

### SNM (Static Noise Margin) and DNM (Dynamic Noise Margin) confusion in digital circuits

I've found in several sites that SNM is the min between NMH and NML where NMH=VOHmin-VIHmin and NML=VILmax -VOLmax But this paper really confuses me, because it uses the same graphics and apparently ...
75 views

### Determining required signal SNR (beat signal from FMCW RADAR)

I'm trying to determine the SNR required for signal outcoming from FMCW Radar. This is the chain: signal will created by "24 GHz VCO and PGA with 2-Channel PA Output" by triangle shape frequency ...
110 views

### Maximum rate Shanon Hartley

i am reading computer networks and i am trying to solve an excercise. the excercise is What is the theoretically the maximum rate at which data can be transmitted to a 4000Hz bandwidth ...
92 views

### Oscilloscope averaging and standard quantum limit

Oscilloscopes give a Vrms noise and have a noise floor, but if I average for a long time to infinity, am I at the standard quantum limit and does SNR keep improving with the sqrt(N averages) forever?
73 views

### noise of high speed serial link

I have an ADC module. The board contains sensitive (10-100MHz) analogue parts and a high speed serial link (Aurora). The link uses scrambling algorithm, and I can choose the bit-rate. (I have much ...
432 views

### Bandwidth-Noise-SNR relationship

Let’s say we have the noise figure F of a system of devices. We also have the bandwidth improvement coefficient ( as defined by my teacher ) $$BI=10log(\frac{B_{in}}{B_{out}})$$ where B1 is the ...
152 views

### high frequency vs low frequency lock-in regarding signal to noise ratio

I understand that the lock-in technique came about in an effort to improve signal to noise ratio. There are lock-in amplifiers operating in high and low frequency regimes. In the context of signal ...
40 views

### Is this SNR change related to aliased common mode noise or some other phenomenon?

Below time series offset value of a force transducer amplifier which is sampled by a 16-bit single ended earth grounded data-acquisition board at 500Hz (red plot) and 12kHz (green plot). Before I was ...
48 views

77 views

### How to obtain maximal voltage transfer?

I have a 50-ohm source which is the output from a photodetector, and I'm using a digitizer card which has 50-ohm inputs, reducing the signal voltage by a factor of 2. The information I care about is ...
1k views

### Op-amps, why do they have such low output currents

An introduction to my question is that ultimately op-amps drive something with their output stage (i.e., they source or sink current). I am looking specifically at the current sourcing scenario for ...
57 views

### How are higher dimensional sphere packings used in signal transmission?

How are higher dimensional sphere packings (HDSPs) related to the error-correcting codes used by cell phones, space probes and the Internet for signal communication through noisy channels? HDSPs ...
125 views

### 3 dB Noise Figure

A noise figure of 3dB, translates to an equivalent noise temperature equal to the room temperature. What is the significance of this relation? Is there a physical interpretation for this?
221 views

### S/N Formula with probability

Hello I am looking for the S/N formula that incorporates the probability of catching the signal, and setting an arbitrary treshold level above which we detect the signal. I can't figure out the ...
137 views

### Is the use of a Lock In with a signal generator appropriate and practicable?

I want to generate a 5 kHz microwave pulse to induce a sample signal. This microwave pulse has an underlying microwave frequency of 2 GHz. In order to investigate very tiny signals, which should arise ...
98 views

I always wondered why ADC is not considered for noise figure measurement in receiver chain? Do ADCs will not have much impact on noise figure in signal processing? How to derive a Noise figure spec ...
246 views

### Sending PWM signals over wire

I'm sending two complementary PWM signals from a control board to a separate power board via a ribbon cable (along with some other signals, 20cm or so). The PWM signals control a MOSFET driver on the ...
339 views

### Am I using Shannon-Hartley Theorem and thermal noise correctly here?

I'm trying to learn about noise, sensitivity, and the Shannon-Hartley theorem, and I'm using some specs for a LoRa node IC to try it out. The Shannon-Hartley theorem says that the maximum data rate \\$...
112 views

### Optimizing dynamic range for acquisition of noisy signal

Is there a good rule of thumb for setting the gain of a noisy signal before digitization? Say I have a 16-bit ADC with a ±1V range; to what level should I amplify the noise floor of my signal relative ...
325 views

### Confusion with the relation between SNR, voltage divider and amplifier concepts

Imagine you have an input signal s(t). And the signal of course has some noise n(t). So lets say the SNR value is x. Now if we attenuate this signal by a voltage divider by 100 lets say, will the SNR ...
205 views

### Limiting Current interference in Photomultiplier Amplifier Circuit

I've been working on a circuit for a while now. It's a circuit consisting of 4 Silicon Photomultipliers, MicroFJ-60035-TSV, in parallel all going into an op amp circuit. I posted questions about it ...
1k views

### How to measure Noise Figure of LNA

I know how to calculate Noise figure of an amplifier on the paper but how can measure Noise figure of a LNA in real world? Our lab doesn't have a fancy Noise figure meter but I can readily access to ...
644 views

### How to amplify a tiny signal riding on a large common mode square wave

I have a small signal of about 10uV-100uV riding on about 1V common mode. I have tried to depict this in the picture. I am interested in designing a board level circuit(cannot use a commercial lock-in ...
260 views

### How can I filter out sunlight on a solar panel so that I can read a signal from a red laser?

So right now I have a small solar panel (4" by 4") and a red laser. I'm trying to design a laser tag system that doesn't follow the way that traditional laser tag is done. I want to be able to shoot a ...
492 views

### Microphone saturation avoiding desired signal from being detected

I'm trying to detect a known signal under heavy interference. I'm working with 2 smartphones and an interfering speaker. I'm sending a signal from one smartphone speaker to the other smartphone ...
1k views

### Amplifying a nV signal across a small resistance

I am interested in the feasibility of amplifying/measuring a nV level (or otherwise assumed very small) signal across a small resistance. The SNR of this signal isn't so bad in itself because of the ...
3k views

### How to properly clean up a noisy signal with a capacitor

I'm reading a pulse from a camera back to a raspberry pi and the noisy signal is causing the gpio pin to read too many inputs. My signal is 3.3v. I'm currently using a 1uf Cap to try to clean up the ...
347 views

### How can a USB cable extender boost the signal without an external power source?

I've been searching online for a USB Cable extender for a rather long distance (let's say 10 meters). I'm familiar with the notion that the longer the cable, the weaker the signal might get, more ...
82 views

### How does using double antennas (one with delay) and adding their output help the SNR?

This is a question our professor asked us to think about. Suppose that we have a communication system with no interference with no channel imperfection but Ergodic AWGN noise. We use two antennas with ...
114 views

### Adding Controlled Noise to Signal

I want to add noise to some signal. I have the option to add the noise via the software API of the system. But I also have the option to add the noise in the hardware circuit itself so there is no ...