Amplitude Shift Keying

[khairulnisa]

i am required to obtain modulated and demodulated signals using Multisim Software according to below techniques:

Amplitude Shift Keying (ASK)

but the prob is i cant find the circuit for this topic..i just need a simple circuit so that it will easy to do simulation using mulstism/pspice or other software related..hope someone can help me..

 

[crutschow]

What is the ASK code? Is it ON/OFF or multi-level?

 

[Sceadwian]

https://en.wikipedia.org/wiki/Amplitude-shift_keying
Please do at least basic research before posting here.
On off keying is generally very prone to picking up noise. Using two discrete amplitude levels is significantly more reliable.

A good example of a practical use of this is the U.S.'s Colorado based atomic clock that broadcasts at 60khz. It's primary power output is 'dimmed' by 17db for 200ms every second to signify a 0, and for 500ms to signify a 1 and 800ms to mark a frame. The leading edge of each ASK pulse denotes the exact mark of a second to within 100micro seconds less the transmit delay.

**broken link removed**

 

[crutschow]

https://en.wikipedia.org/wiki/Amplitude-shift_keying
Please do at least basic research before posting here.
On off keying is generally very prone to picking up noise. Using two discrete amplitude levels is significantly more reliable.

And please read my response more carefully.

My question was about the (type of) ASK code he needed to simulate, not what it is or which type is best.

On off keying has been used since the beginning of radio to send Morse code and it's worked well for that purpose, even if it is, perhaps, not optimum.

 

[Roff]

Linear Technology's LTspice has modulator models in its library that will allow you to do FSK.
EDIT: As Sceadwian pointed out below, I meant to say ASK.

 

[Sceadwian]

I wasn't responding to you or anything you said crutschow. On/off shift keying is the most basic form of ASK, which is what the original poster was asking about. I simply mentioned that on/off keying was prone to noise and that as you call it multi level keying is more reliable, two/multi level ASK becomes on/off shift keying when the 'low' level is lower than the level of detection of the receiver, they're essentially the same thing, with different practical uses.
Due to advances in both analog and digital transceivers, on/off shift keying is effectively obsolete. Not necessarily useless, but still obsolete.

Roff. I fail to see why you mention frequency shift keying when the poster wants to know about amplitude shift keying?

 

[Roff]

I wasn't responding to you or anything you said crutschow. On/off shift keying is the most basic form of ASK, which is what the original poster was asking about. I simply mentioned that on/off keying was prone to noise and that as you call it multi level keying is more reliable, two/multi level ASK becomes on/off shift keying when the 'low' level is lower than the level of detection of the receiver, they're essentially the same thing, with different practical uses.
Due to advances in both analog and digital transceivers, on/off shift keying is effectively obsolete. Not necessarily useless, but still obsolete.

Roff. I fail to see why you mention frequency shift keying when the poster wants to know about amplitude shift keying?

Oops! I meant to say ASK. They will also do FSK, though.

 

[Mikebits]

For Multisim, you can use the Voltage controlled Squarewave Osc in the source symbol library.
See pic below.
Of course replace the switch with your own modulation control circuit.

 

[Mikebits]

Do you ever get the feeling that once the OP ask the question and does not get the immediate answer, that they just move on to another forum never again to read the answers. We end up just posting answers to ourselves. lol

 

[Roff]

Do you ever get the feeling that once the OP ask the question and does not get the immediate answer, that they just move on to another forum never again to read the answers. We end up just posting answers to ourselves. lol

Frequently.

 

[Sceadwian]

Gives us something to argue about though =)