Questions tagged [spectrum]
The spectrum tag has no summary.
94 questions
1 vote
0 answers
53 views
Obtain phase spectrum from frequency/phase modulated signal
I have a homodyne rf setup in which I measure spectra by stepping frequency by frequency. The phase reference resets every time I change the signal frequency, so I can only measure the amplitude, but ...
- 11
5 votes
2 answers
591 views
Strange comb spectrum found during EMI precompliance
During near field testing I encountered this thing I've never seen neither on the wild nor on the book. The board has an STM32F107 with an 8MHz crystal and no ferrites or choke whatsoever (I'm ...
- 9,036
1 vote
1 answer
197 views
On the understanding of signals from an IR detector coupled to a lock in amplifier
I have a CW laser which is modulated by an optical chopper rotating at 1kHz. The modulated CW beam struck a sample holder and the absorption signal is recorder via an Infrared Associates MCT detector. ...
- 109
-2 votes
1 answer
130 views
What two laws of harmonics are demonstrated here? [closed]
I clipped the top and bottom of a sine wave at exact reciprocal angles (73.73159173° to 106.2684083° and 253.73159173° to 286.2684083°) to prevent the creation of even (red) harmonics (by being ...
0 votes
1 answer
61 views
Is it possible to to use same frequency band and same frequency blocks for two adjacent/near telecom circles
As shown in the Screen-Shot, TRAI (Telecom Regulatory authority of India) in the pre-auction recommendation manual to DoT(Department of telecommunication) mentions 770 MHz of the spectrum ( 35 MHz for ...
- 3
1 vote
1 answer
189 views
Op-amp chopping principle in frequency domain to reduce offset voltage
I am trying to understang the chopping principle used in op-amps with help of this document (page 19 - 20.) I understand that switch S1 (aka modulator M1) causes modulation with 1/2 duty cycle and it ...
0 votes
1 answer
188 views
Why do we take 50 ohm resistance value for unit conversion in Spectrum View in the oscilloscopes?
While we change the unit in Spectrum View, why is it explicitly mentioned 50 ohm? Why don't we take the resistance value of 1 Mohm into account as well? Though we do have 1 Mohm as one of the ...
- 11
7 votes
2 answers
2k views
Measuring signal with of nanosecond pulse width with a spectrum analyser?
I'm looking to measure the signal width of electronic signals (device under test, DUT). The problem is that these signals have a quite short pulse width which would require me to use a GHz ...
- 353