According to my understanding of FM, the peak of the audio amplitude corresponds to a frequency in the upper sideband, and the trough corresponds to a frequency in the lower sideband, with one sideband on each side of the carrier.
Now, I know that AM is the same structure of two sidebands and a carrier, but modulated by amplitude. However, why is does AM work for DSB-SC and SSB modes, and not FM? The frequency is mirrored in each sideband in FM, just the same as the amplitude in AM, and SSB has no problems with cutting out the carrier and one sideband. Within the receiver, SSB restores the other sideband before going to the detection circuit; why can't an FM receiver do the same?
Of course, SSB still has the entire audio waveform modulated onto one of the sidebands, but since the troughs are just opposite the peaks for the audio signal waveform, couldn't an FM receiver take the indicated peaks from one sideband and correspond the troughs into the other? You aren't trying to make a physically impossible no-trough RF wave, you would just see the peaks of the audio waveform expressed via frequency in one of the sidebands.
Now, I know that being slighty out tune with SSB results in the "Donald Duck" sound, since there isn't a carrier reference. I would think single sideband FM would have the same issue. However, I don't see why FM wouldn't work. Tuning above or below the SSB signal, to my knowledge, simply results in the high or low frequencies in the modulated audio signal to be cut off, thus resulting in a change in pitch; would the issue with FM be the same, or would it be clipping instead?
If the filter method for SSB doesn't translate with FM, then what about the phasing method?
It doesn't help that my inexperience and lack of radio knowledge has probably caused me to misunderstand some things in my references, nor that I don't understand the math yet. Of course, my understanding is certainly limited; I'm not pretending that I "know" it would work. I'm just trying to understand why it would or wouldn't.
Sources:
[1. part 1 of an old Army video about FM] (https://www.youtube.com/watch?v=gfz1FbIOMbs)
[2. graph-oriented explanation of the phasing method] (https://www.dsprelated.com/showarticle/176.php)
[3. math-oriented explanation of the phasing method] (http://midas.herts.ac.uk/helpsheets/tims/TIMS%20Experiment%20Manuals/Student_Text/Vol-A1/a1-07.pdf)
[4. Wikipedia article about DSB-SC] (https://en.m.wikipedia.org/wiki/Double-sideband_suppressed-
... keep reading on reddit ➡Shouldn't there be only the carrier wave frequency? I've seen it explained using algebraic equations however, I find it non-intuitive and have a hard time just assuming it somehow works this way. Is there any other, more intuitive explanation?
I already tried google but still can't find any, or maybe i don't have the right keywords.
Its been raining here on and off most of today, so i decided to take a rain day and stay home and get into some projects. So i hooked in and build and tested the PA section of the DSB HF HT that I am building. Its taken awhile, but i actually build something I designed that worked as it did in simulation. More details at https://robs-blog.net/2020/01/16/amplifier-voodoo/
When AMC started running, GME stayed neutral. When they tried to do a small flash crash on AMC, GME started running right at the end.
Can someone confirm?
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Also do each of the harmonics (2, 3, 4, etc) from the modulator modulate each of the harmonics from the carrier creating a massive web of sidebands.
1 So M2 (modulator harmonic 2) modulates C2 (carrier harmonic 2)...
M2 modulates C3, M2 modulates C4, etc. Also M3, modulates C2, C3, C4, etc? M4 modulates C2, C3, C4, etc?
Or 2. does M2 only modulate C2, M3 only modulates C3, etc?
Which one is it?
Hey folks, I'm not a trucker but I always have wanted to. I have a question. How do aux transmissions work, and could someone explain double stick or even triple stick shifting? Thanks!
Why is the total average power (Ec)^2 /R + 2*(Em/2)^2 /R? Shouldn't it be something like (Ec+Em)^2 /R because the superposition theorem does not apply to power?
Lattice compression through hydrostatic pressure is an effective way to tune the structural and optical properties of two‐dimensional (2D) halide perovskites ‐ a new class of emerging materials for photovoltaic and light‐emitting applications. However, few examples exhibit improved photoluminescence (PL) performance of 2D perovskites upon compression. It also remains unclear how the pressure‐induced structural changes affect carrier trapping, which is critical for the optoelectronic properties of halide perovskites. Here, we show a remarkable PL enhancement by 12 folds using pressure to modulate the structure of a recently developed 2D perovskite (HA)2(GA)Pb2I7 (HA = n‐hexylammonium, GA = guanidinium). This structure features an extremely large cage previously unattainable, affording us a rare opportunity to understand the structure‐property relationship and explore emergent phenomena in halide perovskites. In situ structural, spectroscopic, and theoretical analyses reveal that lattice compression under a mild pressure within 1.6 GPa considerably suppresses the carrier trapping, leading to significantly enhanced emission. Further pressurization induces a non‐luminescent amorphous yellow phase, which, surprisingly, is retained and exhibits a continuously increasing bandgap during decompression. When the pressure is released to 1.5 GPa, intriguingly, emission can be triggered by above‐bandgap laser irradiation, accompanied by a color change from yellow to orange. The obtained orange phase could be retained at ambient conditions and exhibits two‐fold higher PL emission compared with the pristine (HA)2(GA)Pb2I7. Our findings not only reveal extraordinary pressure‐induced variations and their underlying mechanisms in 2D halide perovskites but also demonstrate the formation of a new phase with enhanced properties at ambient conditions.
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