Thread: how do digital and anloag siginals store information?

How do siginals store data? In the case of a digital siginal, it can have a state of high (1) or low(0), so I assume after a set amount of time (e.g. 1 microsecond?) the receiver checks the value and interprets it using the binary system. Example: low-time passes-low-time passes-high-time passes low would give 0010 which could be interpreted by a computer?

What I really don't get is analog signals because the wave is continuous, how can any data be obtained from them? Is it that the receiver thinks "ok, this wave has an amplitude of 5 so that means the letter 'D' and now the wave has changed to and amplitude of 6 so that's '!'"?

Originally Posted by superdude

How do siginals store data? In the case of a digital siginal, it can have a state of high (1) or low(0), so I assume after a set amount of time (e.g. 1 microsecond?) the receiver checks the value and interprets it using the binary system. Example: low-time passes-low-time passes-high-time passes low would give 0010 which could be interpreted by a computer?

What I really don't get is analog signals because the wave is continuous, how can any data be obtained from them? Is it that the receiver thinks "ok, this wave has an amplitude of 5 so that means the letter 'D' and now the wave has changed to and amplitude of 6 so that's '!'"?

Analog to digital converters can convert an analog amplitude into a binary representation.
Resistor networks can scale the analog signal to an upper and lower bound,
suitable for the converter specifications.
The voltage range can then be scaled into $\displaystyle 2^n$ divisions,
depending on the resolution of various converters.

but if an analog signal is a wave on a wave, how can a wave be interpreted as information? Is it because the type of wave (e.g. specific frequency) represents something?

Originally Posted by superdude

but if an analog signal is a wave on a wave, how can a wave be interpreted as information? Is it because the type of wave (e.g. specific frequency) represents something?

Yes,

the information would be the "modulation of the wave".
It is a change in some parameter of the wave.
It could be amplitude modulation (very old-fashioned),
frequency modulation, phase modulation.

The wave is first demodulated and the information stored in digital form,
after suitable conversion.

So a wave with a specific characteristic(parameters) represents a byte of data?
For example, amplitude 2, wavelength 3 etc. represents "A"
Then why do they say an analog signal can hold more than a digital signal?

Originally Posted by superdude

So a wave with a specific characteristic(parameters) represents a byte of data?
For example, amplitude 2, wavelength 3 etc. represents "A"
Then why do they say an analog signal can hold more than a digital signal?

No, any analog measurement of a parameter can be converted into 16 bits, 32 bits, 64 bits, 128 bits etc depending on the converter.
It's just a matter of choosing the resolution.
An analog signal is similar to the continuum of real numbers,
while the digitized version is akin to naturals.

Could you recommend something I could reed that explains this in detail?