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# Questions tagged [signal-to-noise]

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139 views

### On the Channel capacity

If we are told that the instantaneous SNR at a specific frequency $f$ is $\gamma$ (We do NOT assume that the channel is AWGN but we are only interested in the capacity in bit/s/Hz at this ...
586 views

### How does Hybrid Ground Works?

The text that is above the figure is from my textbook and i am having difficulty to understand what it is trying to say because it's not in detail!! why only remove high frequency and prevent low ...
326 views

### Noise can be Differential or Common!

I have a basic understanding on this topic but i still have some doubts, my text books says Differential means it will have impact on one of the 2 signal nodes. and Common will have a common impact on ...
1k views

### Why is one return conductor for each forward conductor in a ribbon cable better than a shared return conductor?

I don't understand why second way of implementing is better than the first one? I have my own basic logic regarding this topic, but i am not confident if what i think is correct! so i was looking ...
89 views

### reducing the effect of a parasitic capacitor!

According to my text book, the second figure says that the noise current returns to their source without flowing through z1, how is that possible? if the noise returns why doesn't signal/ original ...
56 views

### What is a good wiring configuration to minimize noise on an analog DC signal? [closed]

I am measuring a photodiode with a high precision ADC, but they are currently 0.5-1m apart. The voltage will be constant. I would like to take the measurements as quick as possible so it would be good ...
3k views

### What is the FM threshold effect?

I came across a picture ( shown below ) comparing the SNRs of FM and AM. There was also some explanation of the FM threshold effect and how the threshold effect is the reason as to why the FM graphs ...
229 views

### Simulation of BPSK in fading channels

I'm trying to simulate BPSK in a channel with Rayleigh fading and AWGN, then obtain the Bit Error Probability (BEP). My program is written in C. I compared my BEP vs $\frac{E_b}{N_0}$ (SNR per bit) ...
312 views

### Is it sensible to always use larger diameter conductors for carrying smaller signals?

This question as originally written sounds a little bit insane: it was originally asked to me by a colleague as a joke. I am an experimental NMR physicist. I frequently want to perform physical ...
226 views

### Johnson noise with amplifier circuit

I need help with this problem. Some numerical answers would also be very helpful.
277 views

### How are the original signal and the AM signal related?

Use the TIMS “Variable DC” module to generate a 1V DC signal. Use the “Adder” module to add this DC signal to the message signal generated in task 1 (this will produce the ...
832 views

### Ringing in OPamp OutPut

I am using this Differential In/Out Opamp circuit as ADC driver and to provide some gain(G=6.4). The component values are R53,R52=100, C28, C27=1.1uF, R56= 1K, R57=open, R55,R54= 2K7, U6=OPA2211. At ...
321 views

### Thermocouples - Understanding signal vs. power grounds

I have a simple circuit that reads a temperature and toggles a valve. The thermocouple functions when the dotted ground wire is unplugged, but fails otherwise. Minor edit: The 3.3V going into the ...
170 views

### Is GNSS S/N equivalent to C/N?

I work in developing software that integrates with GPS and Galileo receivers. I've struggled for years with inconsistencies in documentation for the NMEA emitted by such receivers, and I've decided to ...
1k views

### Calculating Data rate function of bandwidth and SNR

I plotted BER vs SNR for BPSK modulation in Matlab and I am given bandwidth of channel (bandlimited channel). lets say it is BW1. I would like to find the data rate based on this information. I am ...
743 views

### Differences between preamplifier, instrumentation amplifier and LNA

I am confused about the definitions of these amplifiers. It seems LNA is used for RF frequency band but I also see people using INA's for receiver. Why LNA's need careful impedance matching but INAs ...
161 views

### misunderstanding from definition of SNR

We know that SNR is defined as "power" of the transmitted signal to the "power" of the noise. In practice we transmit time limited signals (for simplicity consider the case that there is only one ...
512 views

### With regard to GPS signals, what is the significance of I-parts and Q-parts of Complex signal?

What is the significance of I-part & Q-part magnitudes and imbalances in the screenshot? They are listed next to the red Complex signal diagram. Imbalance of I-part: 4.7% Imbalance of Q-part: 25....
259 views

### Sonar single transducer element SNR vs array SNR

Background: I'm taking a flexible learning unit on radar and sonar systems in a vocational college for an assoc. degree level course. The teacher has given us a reading assignment: "Chapter 15 ...
2k views

### How do I find spectral purity?

How is spectral purity measured? or evaluated? I have this signal coming from a 10 MHz crystal oscillator. I know how to calculate the SNR, but how do I calculate the spectral purity? Is it also a ...
240 views

### Decreasing ADC Reference vs. Amplifying signal

I have a sensor interfaced to ADC but the Range I am getting is not enough, so now there are 2 options, Gain up the signal or Reduce ADC Gain. But as I heard it, reducing ADC gain will cause more ...
100 views

### Does the noisy-channel coding theorem (Shannon's theorem) apply to two-way communication with retransmission requests?

Does the noisy-channel coding theorem apply to automatic repeat request systems? Some people seem to imply that, when a system has 2-way communication, such systems can have far lower error rates at ...
3k views

### How to Calculate maximum distance between transmitter and receiver in wireless communication

how to calculate maximum distance between transmitter and receiver in free space radio communication by having transmitted power, antenna gain and noise-to-signal ratio ?
3k views

### How to select gain for an amplifier before ADC?

The circuit has been simplified as shown in the picture. Signal source is connected with an analog amplifier, which amplifies the ac signal and also raise it by 1.5V to match with the range of the 0-...
98 views

### What does it mean exactly “ averaging over eight symbol periods” when calculating RSS?

When reading about RSSI, I usually found that RSSI is measured by averaging the signal reading over eight symbol periods, I could not understand what does it mean exactly and how RSSI is calculated by ...
467 views

### Opamp Noise due to Source Resistance

I want to know total noise I am feeding into ADC and I have learnt about Opamp Noise and resistor noise thanks to this forum. Now I want to know the contribution of resistor in my overall noise due to ...
2k views

### Difference between SINR SNR

I am bit confused between these two terms. I understand SINR is signal to interference+ noise ratio and SNR is signal to noise but isn't interference noise too? Then why have he segregated these two ...
2k views

I want to calculate theoretically my effective resolution from C8051F350 in-built sigma delta ADC with different interface options like ISL28134, ADA4528, ADA4898, OPA211, mcp6v07. I want to know ...
2k views

### Link Capacity and the Shannon-Hartley Theorem

I'm reading Computer Networks: A Systems Approach by Peterson and Davies. One of the examples demonstrates the relationship between link capacity and the Shannon-Hartley Theorem. We can find the ...
2k views

### ENOB Calculations

I've been having a discussion with a colleague about ENOB (effective number of bits) calculations for DACs and ADCs. We both come across it from different directions (he being more analog, and me ...
157 views

### Nature of noise gotten from digital oscilloscope

I've got strange noise while using digital oscilloscope (Auris B-424). Spectrogram of this signal presented on this image: (X time in seconds, Y frequency in Hertz, in this image case from 0 to 50 MHz)...
2k views

### How to characterize SNR for an amplifier with extreme low input signal?

Often that the OPAMP has an internal noise of 1uV. If I have an extreme high gain of 10000, the noise will be amplified up to 0.01V. Then, when I input a very low input signal of 10uV, after amplify ...
91 views

### QAM's performace and SN

1) QAM's signal formula is $$s(t) = I(t)sin(2\pi f t) + Q(t)cos(2\pi f t)$$ The I axis and Q axis are orthogonal to each other, but its angle is 45 degrees, or 30 degrees. At how many degrees does ...
113 views

### Signal to noise ratio for a non-physical property

The signal to noise ratio for a voltage, current, or power is easy to understand, but how do I calculate the SNR when the signal is not a physical property, but instead an abstract quantity? I'll try ...
2k views

### Trifilar Transformer Common-Mode Rejection Circuit (Signal Recovery, Hybrid Combiner, RF)

I'm trying to develop a circuit that allows me to effectively subtract two different sources of RF noise from a single signal at the same time. I am planning to use something called a "trifilar" ...
927 views

### SNR improvement from placing analog filter ahead of digital filter

We have designed a PCB containing a data collection circuit for a customer, and their external expert presents this "helpful suggestion": Question about signal averaging vs. longer integration ...
157 views

### How to decide to cuttoff frequecies of filter in case of using ADC( Flow: Analog-signal to ADC to bits to fir_filter to filtered_output) [closed]

FIR filter has to be used for removing the noise. I don't know the frequencies of the noise that might be adding up into the analog feedback signal I am taking. The ADC has takes just a voltage value ...
10k views

### Why Decibels are used to measure Signal to Noise Ratio?

We just started a communications course in college and we came across SN ratio. The following is an ambiguity I am facing which my professor is unable to resolve: Signal to Noise Ratio is the ratio ...
1k views

### Detection of weak periodical sound signal having negative SNR (will lock-in-amplifier be useful)

I'm trying to understand whether it is possible to detect human's heartbeat from a distance. I'm not a specialist, but it seems to me that the following issues must be addressed: Very sensitive ...
378 views

### Minimum tolerable signal to noise ratio in modern communication systems

What is the minimum tolerable SNR in today's (digital) communication systems for successful recovery of the message? I've heard that regular commercial systems can recover the message with a SNR as ...
2k views

### Signal to Noise ratio problem

A 200mv peak to peak sinusoidal signal is applied to an ideal 12 bit A/D converter, for which Vref(v p-p full scale) is 5v. Find signal to noise ratio. This is a problem worked out by one of my ...
9k views

### Attenuator noise figure and loss

My question is with regard to how attenuators effect noise. From what I understand  \text{NF} = 10\log \left( \frac{S_{in}/N_{in}}{S_{out}/N_{out}} \right) = 10\log \left( L \frac{N_{out}}{N_{in}} \...
461 views

### How is noise reduced using a sigma-delta converter?

Perhaps I'm sleepy but I can't quite get my head around how a sigma delta converter takes the noise that is in a bandwidth of (X) Hz and by over sampling spread, that same amount of noise over 2(X)Hz. ...
5k views

### False Positives on Arduino Input

I've used analog and digital input for a multitude of applications with the Arduino Uno board. It has continuously given extremely non reliable readings, where the analog input is always fluctuating, ...
2k views

### How to split Analog and Digital GND planes for a TQFN device

This question is in reference to Mixed signal PCB layout for PSoC. If I am using a microcontroller which has separate analog and digital supply inputs and GNDs, what should do with the grounds? ...