digital transmitters and recievers
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Posts: 46,084
Sorry,·help with a schematic if·I dont know what the circuit is supposed to do.· The question that you present are extermely general and would take much more explanation and research to do whatever it is you are trying to do than you will probably find on a mailing list.· You would need to know what kind of medium you wanted to transmit in (air, water etc), what frequencies (HF, VHF, UHF), the power output of the transmitter,·whether or not the system is half-duplex or full-duplex etc (does transmitting and receiving occur on the same channel or different channels), what kind of modulation is being used (amplitude modulation (AM), frequency modulation (FM),·what kind of amplification will be necessary when the signal is received from the antenna, what kind of antenna etc....·
One would need alot of engineering theory and math before·truly·beginning to understand·what it is you are interested in.· To convert a signal from analog to digital a analog-to-digital converter (ADC) is needed.· The resolution of the ADC would·be pretty important to know.· You would need to know what the maximum frequency of the analog signal is so that the sampling would occur at twice that frequency (Nyquist Rate) to avoid a condition known as "aliasing" which would lead to a misrepresentation of the original analog signal when it is converted back from being a digital signal with a digital-to-analog converter (DAC).· Basically, the answer to your question isn't a one-liner.·I don't understand it all myself and I·have been·schooled in Electrical Engineering.· That's all the info I can think of to give to you.·
Hope that helped,
Jim
Original Message
From: Alicia Sanchez
To: basicstamps@yahoogroups.com
Sent: Monday, February 05, 2001 10:29 PM
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
hello,
i need some assistance when it comes down to digital recievers and digital transcievers.· I need shematics and and explanation of the way you can change them from analog to digital.· Can you help?· Or at least try.
thanks alicia
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One would need alot of engineering theory and math before·truly·beginning to understand·what it is you are interested in.· To convert a signal from analog to digital a analog-to-digital converter (ADC) is needed.· The resolution of the ADC would·be pretty important to know.· You would need to know what the maximum frequency of the analog signal is so that the sampling would occur at twice that frequency (Nyquist Rate) to avoid a condition known as "aliasing" which would lead to a misrepresentation of the original analog signal when it is converted back from being a digital signal with a digital-to-analog converter (DAC).· Basically, the answer to your question isn't a one-liner.·I don't understand it all myself and I·have been·schooled in Electrical Engineering.· That's all the info I can think of to give to you.·
Hope that helped,
Jim
Original Message
From: Alicia Sanchez
To: basicstamps@yahoogroups.com
Sent: Monday, February 05, 2001 10:29 PM
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
hello,
i need some assistance when it comes down to digital recievers and digital transcievers.· I need shematics and and explanation of the way you can change them from analog to digital.· Can you help?· Or at least try.
thanks alicia
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
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Comments
For digital transmitters and receivers they could be RF or IR.· There are different modulation schemes as well.· There is what is known as frequency hopping (FH)·spread spectrum as well as direct sequence (DS) spread spectrum.· I would begin to look at IEEE 802.11.· This is a wireless networking standard for both IR and RF.· These radios operate at the 2.4 GHz bandwidth (same frequency as a microwave oven so if your looking for high power applications,·tie up your cat (get it hehe)· Actually the FCC limits power output to 1 Watt which will operate effectively only a few hundred feet at most.· You could also look up the Bluetooth standard.· Both standards are pretty hi-tech but what you are trying to learn about is pretty hi-tech.· For more info on 802.11 you can go to www.iol.unh.edu
Good Luck,
Jim
Original Message
From: Jim Szymczak
To: basicstamps@yahoogroups.com
Sent: Monday, February 05, 2001 4:48 PM
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
Sorry,·help with a schematic if·I dont know what the circuit is supposed to do.· The question that you present are extermely general and would take much more explanation and research to do whatever it is you are trying to do than you will probably find on a mailing list.· You would need to know what kind of medium you wanted to transmit in (air, water etc), what frequencies (HF, VHF, UHF), the power output of the transmitter,·whether or not the system is half-duplex or full-duplex etc (does transmitting and receiving occur on the same channel or different channels), what kind of modulation is being used (amplitude modulation (AM), frequency modulation (FM),·what kind of amplification will be necessary when the signal is received from the antenna, what kind of antenna etc....·
One would need alot of engineering theory and math before·truly·beginning to understand·what it is you are interested in.· To convert a signal from analog to digital a analog-to-digital converter (ADC) is needed.· The resolution of the ADC would·be pretty important to know.· You would need to know what the maximum frequency of the analog signal is so that the sampling would occur at twice that frequency (Nyquist Rate) to avoid a condition known as "aliasing" which would lead to a misrepresentation of the original analog signal when it is converted back from being a digital signal with a digital-to-analog converter (DAC).· Basically, the answer to your question isn't a one-liner.·I don't understand it all myself and I·have been·schooled in Electrical Engineering.· That's all the info I can think of to give to you.·
Hope that helped,
Jim
Original Message
From: Alicia Sanchez
To: basicstamps@yahoogroups.com
Sent: Monday, February 05, 2001 10:29 PM
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
hello,
i need some assistance when it comes down to digital recievers and digital transcievers.· I need shematics and and explanation of the way you can change them from analog to digital.· Can you help?· Or at least try.
thanks alicia
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Get your FREE download of MSN Explorer at http://explorer.msn.com
i need some assistance when it comes down to digital recievers and digital transcievers.· I need shematics and and explanation of the way you can change them from analog to digital.· Can you help?· Or at least try.
thanks alicia
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
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Internet to get an idea how big).
However, this may be overkill for you. For example, if you are trying to use
an "on/off" transmitter to send an analog quantity, there are several tricks
you can play. For instance, you might use a voltage to set a 555's threshold
and generate a varying pulse width. The width of the pulse would be
proportional to the voltage. You can key the transmitter with that pulse and
use the received pulse width to determine the voltage. This is more or less
how R/C cars/planes/etc operate. Of course, you must take into account
noise, etc. and the resolution isn't stellar without using some tricks.
If your analog quantity is a resistor or capacitor (like a joystick or a
thermistor) this is even easier since generating pulses from an RC is quite
simple. There are some specific V to F chips out there too (voltage to
frequency).
If, however, you mean you want to digitize audio (or heaven forbid, video)
and transmit it digitally, that is a very big question on the order of How
can I design a TV set!
Al Williams
AWC
* Floating point math for the Stamp, PIC, SX, or any microcontroller:
http://www.al-williams.com/awce/pak1.htm
Original Message
From: Jim Szymczak [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=rTZoYYSDL052KbUsaEH7DjWw8SD85MsQi-i_lDSgIhp1YcfaoeprnlfZ1NI_X4fcFur6YL7nBX7q5UYZF0jaFg]szymczak@c...[/url
Sent: Monday, February 05, 2001 3:48 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
Sorry, help with a schematic if I dont know what the circuit is supposed to
do. The question that you present are extermely general and would take much
more explanation and research to do whatever it is you are trying to do than
you will probably find on a mailing list. You would need to know what kind
of medium you wanted to transmit in (air, water etc), what frequencies (HF,
VHF, UHF), the power output of the transmitter, whether or not the system is
half-duplex or full-duplex etc (does transmitting and receiving occur on the
same channel or different channels), what kind of modulation is being used
(amplitude modulation (AM), frequency modulation (FM), what kind of
amplification will be necessary when the signal is received from the
antenna, what kind of antenna etc....
One would need alot of engineering theory and math before truly beginning to
understand what it is you are interested in. To convert a signal from
analog to digital a analog-to-digital converter (ADC) is needed. The
resolution of the ADC would be pretty important to know. You would need to
know what the maximum frequency of the analog signal is so that the sampling
would occur at twice that frequency (Nyquist Rate) to avoid a condition
known as "aliasing" which would lead to a misrepresentation of the original
analog signal when it is converted back from being a digital signal with a
digital-to-analog converter (DAC). Basically, the answer to your question
isn't a one-liner. I don't understand it all myself and I have been schooled
in Electrical Engineering. That's all the info I can think of to give to
you.
Hope that helped,
Jim
Original Message
From: Alicia Sanchez
To: basicstamps@yahoogroups.com
Sent: Monday, February 05, 2001 10:29 PM
Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
hello,
i need some assistance when it comes down to digital recievers and digital
transcievers. I need shematics and and explanation of the way you can
change them from analog to digital. Can you help? Or at least try.
thanks alicia
Get your FREE download of MSN Explorer at http://explorer.msn.com
thanks for the information about the transmitter.·At this moment I am finishing up my bachelor's degree in electronics engineering, and I had a brain fart, and the leader of our group gave me the hardest part of the project: designing and building the tranciever and a reciever to make them into a transiever.· And I need to do two of them.· But the info you gave me re-reminded me what I am suppossed to keep in focus.I keep you informed of my final project.
Thanks a bunch,
Alicia
>From: "Jim Szymczak"
>Reply-To: basicstamps@yahoogroups.com
>To:
>Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
>Date: Mon, 5 Feb 2001 16:48:09 -0500
>
>Sorry, help with a schematic if I dont know what the circuit is supposed to do. The question that you present are extermely general and would take much more explanation and research to do whatever it is you are trying to do than you will probably find on a mailing list. You would need to know what kind of medium you wanted to transmit in (air, water etc), what frequencies (HF, VHF, UHF), the power output of the transmitter, whether or not the system is half-duplex or full-duplex etc (does transmitting and receiving occur on the same channel or different channels), what kind of modulation is being used (amplitude modulation (AM), frequency modulation (FM), what kind of amplification will be necessary when the signal is received from the antenna, what kind of antenna etc....
>
>One would need alot of engineering theory and math before truly beginning to understand what it is you are interested in. To convert a signal from analog to digital a analog-to-digital converter (ADC) is needed. The resolution of the ADC would be pretty important to know. You would need to know what the maximum frequency of the analog signal is so that the sampling would occur at twice that frequency (Nyquist Rate) to avoid a condition known as "aliasing" which would lead to a misrepresentation of the original analog signal when it is converted back from being a digital signal with a digital-to-analog converter (DAC). Basically, the answer to your question isn't a one-liner. I don't understand it all myself and I have been schooled in Electrical Engineering. That's all the info I can think of to give to you.
>
>Hope that helped,
>Jim
>
Original Message
> From: Alicia Sanchez
> To: basicstamps@yahoogroups.com
> Sent: Monday, February 05, 2001 10:29 PM
> Subject: Re: [noparse][[/noparse]basicstamps]digital transmitters and recievers
>
>
>
>
>
>
> hello,
>
> i need some assistance when it comes down to digital recievers and digital transcievers. I need shematics and and explanation of the way you can change them from analog to digital. Can you help? Or at least try.
>
> thanks alicia
>
>
>
> Get your FREE download of MSN Explorer at http://explorer.msn.com
>
>
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