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Questions tagged [amplitude]

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peak detector simulation

I am simulating an AM demodulator using the peak detector in Orcad softwere, but I find a convergence problem, regardless of the simulation time I use. Can you help me to resolve this problem? For ...
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31 views

SGEN amplitude measurement doesn't match oscilloscope

I don't understand the measurements regarding the voltage of the oscilloscope of the JDS6600 signal generator I recently bought. Being the SGEN specified amplitude 5V I'd expect the Vpp on the ...
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2answers
67 views

Unit of ultrasound A-scans

I have a basic question concerning ultrasound A-scans. Such an A-scan might typically look as follows (source: https://img.medscapestatic.com/pi/meds/ckb/18/7418tn.jpg): I understand that the x-axis ...
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1answer
130 views

Understanding function generator output when units are in dBm

I am using a function generator with output in units of dBm. It has an output impedance of 50 ohms. I am measuring this output on an oscilloscope, and am failing to understand the waveform's amplitude....
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2answers
36 views

Time Domain and Frequency Domain Amplitudes

I was wondering about these two graphs, the first is taken from an Oscilloscope and the second is taken from a Spectrum Analyzer. Why is the amplitude in the frequency domain close to 1/3 of that in ...
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1answer
237 views

LT spice: change amplitude of a voltage source over time in LTspice

I would like to have a sinusoidal voltage source that varies over time, for example; for time duration 1msec : 3v 13.56MHz for time duration 2msec : 10v 13.56MHz please help. i studied Help for ...
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3answers
68 views

Convert -dB to equivalent +dB

I asked this question on stackoverflow and stackexchange mathematics, but on both sites my question was closed and suggested to ask here as mentioned in the comments to this question on mathematics. ...
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2answers
288 views

How to automatically “normalise” a voltage signal in LTspice?

I would like to create an output signal that is normalised by the maximum value of a signal in LTspice. This is to produce a signal between [-1, 1] that is suitable for producing a wave file like ...
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3answers
520 views

How to find the charging time of a capacitor given a frequency and an amplitude

In the circuit above, suppose the input pulse signal has an amplitude of 1V and a frequency of 1 kHz. The resistance is 56 kilo-ohms and the capacitance is 1 nF. So if I want to find the charging time,...
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3answers
588 views

High Frequency Rectification

I am trying to monitor an incoming signal and get some properties from it. The signal is a sine wave +-5V at 900Mhz. I am trying to measure the amplitude and the frequency of the signal. I will ...
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1answer
4k views

AM Modulator with BJT 2N3904

I created an AM modulator circuit with BJT 2N3904 for a school project. V1 is the modulating signal (sine wave, amplitude 5V, frequency 1KHz) V2 is the carrier signal (sine wave, amplitude 30mV, ...
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1answer
257 views

How can I increase amplitude without affecting frequency accuracy? [closed]

I have generated a variable frequency generator which generates frequency from 0 to 10kHz, with the amplitude of 4.8-5.2 V. How can I increase the amplitude up until 8V without affecting the accuracy ...
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1answer
103 views

The circuit that gives the higher-voltage one of the two input signals to output

I need a circuit that behaves as the box with the question mark in the graph I drew. I tried to design a few circuits with op-amps but I couldn't get an output as I wanted.
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1answer
80 views

Manipulating Amplitude and Axis of symmetry of BUBBA oscillator in Simulink

So far i have a bubba ocsillator that can produce smooth sinusoidal waves, but the output waveform is asymmetric about the y-axis and the amplitude is not 1. What exactly do i need to do to :- Make ...
6
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1answer
898 views

Why is the signal amplitude low on the oscilloscope even though the impedance is matched?

I have a photodetector with differential outputs that are each 50-ohm terminated. When I connect one output to the oscilloscope to look at the signal, I see a higher signal amplitude with higher ...
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3answers
175 views

Is there a prefered Modulation Index with Pulse Amplitude Modulation? (PAM)

You can vary the modulation index of Pulse Analogue Modulation. For instance, the RF carrier could be 100% modulated on marks, and zero % on spaces. Or, 100% on marks, 50% on spaces. In theory you ...
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1answer
183 views

How to double the amplitude of an AC Signal

If I have an input signal, \$v_{in} = A\sin(2 \pi ft)\$ where 1 < A < 4V and 20 < f < 20 kHz, and I am wanting to double the signal's amplitude so that my output then becomes \$v_{out} = ...
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2answers
346 views

Basic Oscillator Circuit

I am wondering, if the quartz crystal, to be used as part of an oscillator, needs additional components to oscillate at its resonant frequency? And if it does, which are those extra components that ...
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4answers
2k views

What does “shift keying” mean in the context of digital modulation?

English is not my native language and I do not understand why the words "shift keying" were used to describe some types of digital modulation. What does "keying" mean in the context of signals and ...
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2answers
254 views

Envelope detector and DC voltage

I am currently working in the simulation of a physics project. One of the detectors inputs a voltage V1: V1(t)= D+Acos(wt) and tries to extract the amplitude. I read that a simple Envelope detector ...
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2answers
212 views

What is the use of R5, C4, C2, R6, R5, D1 in the below amplitude modulation circuit?

the project is taken from this website for my college project http://www.instructables.com/id/Modulating-Audio-on-a-LED/ I think I have figured out function of few components but still need ...
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3answers
16k views

Peak to Peak vs. Amplitude

For a sine wave, Amplitude is the fluctuation or displacement of the wave from its mean value. Peak-to-peak (pk-pk) is the difference between the maximum positive and the maximum negative amplitudes ...
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1answer
223 views

Why is the calibration signal's amplitude of my oscilloscope 10 times higher than stated?

I'm trying to calibrate my HAMEG HM507 oscilloscope. The manual says that the calibration signal is 0.2Vpp. With the attentuation of the probe set to x10, volts/division set to 5mV/cm, time/division ...
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1answer
770 views

AM Demodulation with Envelope Detector

I have to project an AM demodulator using an Envelope Demodulator. To which kinds of AM (DSB, DSB-SC, VSB, SSD) is it applicable to? Thanks
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1answer
1k views

Power of AM signal [closed]

I need to calculate the power of the sidebands and the carrier. The carrier is 10*cos(2pi10⁶t) [V] and the modulating is 3*cos(2pi10³t) [V]. The modulated signal is 10*cos(\$w_0\$t)+\$\frac{3}{2}\$*...
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2answers
449 views

Signal with little amplitude and offset in LTSpice

i have a problem trying to work with a signal whose amplitude is in nanovolts and has an offset of 1V. LTSpice doesn't plot the amplitude because is too small in comparation to the offset (the ...
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4answers
6k views

In this Amplitude Modulation circuit, what is the purpose of the diode load (L2)?

In this circuit i know that the diode mixes the signal. I know that after the diode it is a half-wave. I know that the capacitor reproduces the lost signal. I have a feeling L2 is maybe plays a part ...
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2answers
130 views

Drawing basic AM signal [closed]

I am confused with how to draw the following AM signal: S(t)=6cos(12t)+3/2cos(14t)+3/2cos(10t)
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380 views

QAM Modulation Frequency vs Carrier Frequency

In QAM (Quadrature Amplitude Modulation) theory what is the relationship between the modulation frequency and the carrier frequency called? It is often stated in QAM tutorials that the carrier ...