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What are the ASK and AM transmitters?

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ASK or AM transmitter?

Hi, all,

I am confused with these terms, ASK and AM. I know one for digital and one for analog. But how exactly they are being used?
Let's say, for RFID application, should I use an ASK transmitter or an AM transmitter?

KK

Thanks.
 

ASK or AM transmitter?

Hi,

I don't know RFID, but I just wanna give a bit explanation on ASK and AM.

ASK as far as I know is only good for transmitting digital information via short cable, not wireless channel. This is because ASK has amplitude fluctuation which is not suitable for amplifier at the transmitter or repeter. So usually people use FSK in wireless communication, instead.

AM is somehow good for transmitting analog signal via wireless channel.

So if your application is to transmit the data via wireless channel, then between ASK and AM, you must choose AM. However, there are some other modulation which suit better, e.g. FM or FSK.

best
 

Re: ASK or AM transmitter?

Hi, Mimomod,
Thanks for your reply.
When you google 433mhz ask transmitter, you will find a lot of wireless chipsets for 433mhz. So people did use ASK for wireless comm. But for audio transmission, people normally use AM because of its analog nature, i think.
Now i am doing a project for low frequency communication system at 70khz. A mcu sends out its ID to the transmitter through digital ways, so I guessed a
ASK gets involved. And do i need to use a AM transmitter after the ASK transmitter? I doubt.

regards
KK.
 

Re: ASK or AM transmitter?

AM stands for Amplitude Modulation, ie a means to send information by modulating the amplitude of the RF carrier. AM could be digital OR analog.


ASK stands for Amplitude Shift Keying. ASK is a digital subset of the wider family of AM modultions. ASK is typically 1 bit--on/off. But ASK could also be 2 bit/4 state, 3 bit/8 state, etc depending on the complexity of the modulator/demodulator.
 

ASK or AM transmitter?

ASK system can use an AM transmitter. But the linearity requirements are less stringent for ASK than for AM, because (analog) AM amplifier needs to be linear in order to have low distortion and out-of band emissions.
In the case of binary ASK (also called OOK, On-Off Keying), the signal simply is switched on and off, and this is very simple with a nonlinear amplifier. There is no need to control the output ampltude.
Regards

Z
 

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