New answers tagged digital-communications
2
I started writing this answer when the question was posted in Space SE, and moved it here as the question moved.
In a laser satellite system we have a much narrower beam... does the distance effect the data rate in laser communication system?
The same calculations (and physics) apply to both laser and radio link budgets. They both start out as collimated ...
0
M refers to mega which is just the number times 10^6. "bps" refers to bits per second which is equal to b/s.
If you use "B" instead of "b" which means Bytes, 8 bits = 1 Byte.
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Actually, your point is true. If you have a narrow beam, the received signal strength will increase (if the receiver's beam is well-aligned through the boresight of the trasmitter beam.) Recall the Friss power transmission formula:
$$P_R = P_T\frac{G_RG_T}{4\pi\lambda^2}$$
where
$P_R$: received signal strength
$P_T$: transmit power
$G_R,G_T$: receiver, ...
0
Yes, you can write 100Mb/s as 100mbps.
b = bits, B = bytes
Mb/s = Megabits per second.
MB/s = Megabytes per second.
Mbps (in some languages mbps) means megabits per second. Mb is used in reference to download and upload speeds. It takes 8 bits of data to equal 1 byte.
In EU area there are few other terms and abbreviations used for the same unit as can be ...
-1
1 Byte = 8 bits
100Mb/s = 800mbps
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I do like @TimWescott answer a lot. less cultural than Shakespeare, the symbol wikipedia page asserts that:
"Symbols are a means of complex communication that often can have
multiple levels of meaning"
and this goes well within our signal processing/information theory/data compression/communication community. The etymology for symbol is often ...
1
The Wikipedia entry for the Nyquist ISI criterion has a good explanation.
Suppose that the symbols to be transmitted are regarded as an impulse train (one impulse every $T$ seconds). At the transmitter, the impulse train is applied to the transmitter pulse-shaping filter producing the transmitted signal, a pulse train, which is then transmitted over the ...
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In the words of that great communications theorist, William Shakespear, "There are more things in heaven and earth, Horatio, than are dream'd of in your philosophy".
The reason it's hard to pin down an exact definition of "symbol" is because it's a really handy concept that can be stretched to aid us in doing a lot of useful math, but an ...
5
The best definition (in the sense of being specific, clear and useful) of a symbol is the following, in my opinion.
In a digital communication system bits are transmitted using an analog (continuous-time) signal. The process of converting from bits to this analog signal is called "modulation". It consists of these steps:
Select a Nyquist pulse $p(...
1
What is a difference between optical and laser communication for satellite?
Lasers are one type of optical communication. I'd guess all satellite optical comms are laser-based.
So, there's no difference.
I have read, in optical communication, no special antennas are needed for communication.
... Unless you realize that a lens is actually just a kind of ...
0
Is there a way to eliminate this texture so that when I mix the recordings, I get one clear and enhanced speech signal?
That depends A LOT on the details: what is your specific setup, what is the main reason they sound different, what exactly do you mean by "texture" and "clean", and what are the specific requirements of your application....
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I feel like the other answers don't make it clear how, when and why and at what stage the matched filter is actually used in a step by step process, before you can actually understand the mathematical explanation. Also there is a confusion about how the reference signal is known.
Instead, the reference symbol template is known. There is a matched filter ...
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In general, the channel coefficient $h$ is a complex number so it has magnitude and phase. Physically, $|h|^2$, is the attenuation/power-loss due to the channel and that is why you include it in the signal power calculation. The signal power is:
$$
\mathbb{E}\big[hx[n](hx[n])^* \big]=|h|^2\mathbb{E}\big[|x[n]|^2\big]=|h|^2P
$$
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Are the PI and IIR LPF filters equivalent?
A PI filter is an IIR LPF, but a low-pass filter is more general. So -- no.
Is my understanding of this "modified" PLL structure correct?
I can't tell, but I think you're lacking in the understanding of closed-loop control systems.
Should the IIR filter work in this case?
Maybe, but it depends on ...
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