Digital wireless systems

[john]

Hi,

I programmed Spartan chip to produce serial data ( main_Clock, Data
Clock, Data and Tag ) stream for a DAC. I need to make this system
work with out wires. The main clock is 3MHz, Data clock is 1.5MHz. Can
anybody advice me how to make it digital wireless ( Transmitter plus
receiver). I have not done anything like this before. The DAC will be
at 6 feet away from the Spartan chip.

Thanks
John

 

[linnix]

Hi,

I programmed Spartan chip to produce serial data ( main_Clock, Data
Clock, Data and Tag ) stream for a DAC. I need to make this system
work with out wires. The main clock is 3MHz, Data clock is 1.5MHz. Can
anybody advice me how to make it digital wireless ( Transmitter plus
receiver). I have not done anything like this before. The DAC will be
at 6 feet away from the Spartan chip.

Thanks
John

The best way is to modulate your signal at 5.8GHz and embed the phase
correction data into the data stream. I assume the data flow is one-
way only.

 

[john]

Hi,

Yes, The data is flowing in one way. Would you please suggest some
hardware. I am also thinking about bluetooth. Please advice!

Regards,
John

 

[linnix]

Hi,

Yes, The data is flowing in one way. Would you please suggest some
hardware. I am also thinking about bluetooth. Please advice!

Regards,
John

Bluetooth will not give you 1.5MHz data rate. In fact, 5.8GHz might
not be enough, but the next ISM band is 25GHz.

 

[john]

Any suggestions regarding Hardware?
Regards,
John

 

[linnix]

Any suggestions regarding Hardware?
Regards,
John

The Atmel ATR2820 RF Transceiver would be a good start, but I can't
design your apps without knowing the full spec.

 

[Rich Webb]

Hi,

I programmed Spartan chip to produce serial data ( main_Clock, Data
Clock, Data and Tag ) stream for a DAC. I need to make this system
work with out wires. The main clock is 3MHz, Data clock is 1.5MHz. Can
anybody advice me how to make it digital wireless ( Transmitter plus
receiver). I have not done anything like this before. The DAC will be
at 6 feet away from the Spartan chip.

One-off project or a few dozen or a few hundred thousand? Per week?

A hobby/learning/grow-your-brain project or for sale (and use) by a
third party?

Will UL/CSA/EC/FCC/etc. certification be required?

Are the consequences of a communications failure: none, benign, pretty
bad, or someone dies?

Is this for a medical application (noting that your IP block is from
Wayne State University Medical Center)?

With that out of the way, if you can grind down the data rate a bit
(no pun intended), you're close to being able to use an off-the-shelf
solution like an XBee module, advertised to top out at 1 Mbps.

<http://www.sparkfun.com/commerce/product_info.php?products_id=8695>

 

[linnix]

One-off project or a few dozen or a few hundred thousand? Per week?

A hobby/learning/grow-your-brain project or for sale (and use) by a
third party?

Will UL/CSA/EC/FCC/etc. certification be required?

Are the consequences of a communications failure: none, benign, pretty
bad, or someone dies?

Is this for a medical application (noting that your IP block is from
Wayne State University Medical Center)?

With that out of the way, if you can grind down the data rate a bit
(no pun intended), you're close to being able to use an off-the-shelf
solution like an XBee module, advertised to top out at 1 Mbps.

Take a look at the RF data rate of 250Kbps. Does it mean the same for
me as for you?

 

[john]

Hi,

What do you think about Texas Instrument's IEEE 802.16 (WiMax) chip
set ( TRF1X/2X RF Chipset ).
Please advice!

Regards,
John

 

[linnix]

Hi,

What do you think about Texas Instrument's IEEE 802.16 (WiMax) chip
No.

set ( TRF1X/2X RF Chipset ).
Maybe.

Please advice!

Forget about Bluetooth, WiFi, XYZBee, WiAnything. If you want
slicings or channelings, you need 25GHz. To get 1.5MHz data rate, you
need the full bandwidth for 5.8GHz.

 

[john]

Why do I need the bandwidth of 5.8GHz. Please advice!
John

 

[linnix]

Why do I need the bandwidth of 5.8GHz. Please advice!
John

Radio Freguency Modulations and Demodulations.

 

[john]

How many bits at the 1.5MHz rate?  In other words, how many Mbps?

Regular old 802.11g wireless routers will get you >50Mbps; channel bonding
(40MHz occupied bandwidth) gets you up to >80Mbps in the best cases... which
is just as good as anything you get on 5.8GHz WiFi.  (These are all *average*
throughputs, taken from the "wireless charts" atwww.smallnetbuilder.com...)

Hi,

48 bits at 1.5Mhz rate?

John

 

[linnix]

Hi,

48 bits at 1.5Mhz rate?

John

Never mind, Bluetooth 2.0 would be fine. I thought you mean 1.5Mbps
sustained.

 

[linnix]

"48 bits at 1.5Mhz rate?"

Not sure if he meant 48 bits per second, per millisecond or per
microsecond.

That's 72Mbps, so you can just manage it with the best WiFi routers out there.

Not so, Wifi are rated at burst data rate, not sustained rate.

 

[linnix]

Sure, the advertised data rate is something absurd like "300Mbps!" But go
read the link I provided -- the best routers absolutely do better than 70Mbps
*on average*. Obviously the speeds gets reduced as you move further from the
router or have other interferers that reduce SNR, but close-in something like
a Belkin N1 will do the job (see:http://www.smallnetbuilder.com/content/view/30238/96/) for under $200.

And you probably want his spartan FPGA to talk ethernet as well.

 

[Rich Webb]

Take a look at the RF data rate of 250Kbps. Does it mean the same for
me as for you?

Apparently not.

 

[linnix]

Yeah... slapping down some gigabit Ethernet reference design is one heck of a
lot easier than slapping down a high-speed wireless router design. If you
look at the reviews, you can see that what often makes the difference between
"solid and fast" vs. "flaky and slow" routers isn't the actual hardware --
which is often very similar, if not identical -- but how much tweaking
occurred in the radio controller firmware. Unless I'm building a radio from
scratch, I'd prefer to let someone else worry about that.

Sure, if we are looking for a $200 solutions, we can build multi-TX,RX
radios. We don't have to deal with channels and/or routings as well.

 

[john]

Hi,

So, I need customized hardware to do this. Are you guys sure that
there are no chips available to do what I want to do? Any suggestions
or pointers that how should I proceed. I have FPGA generated clock and
data stream . Data is 48 bits wide and I am serially outing the data
at 1.5MHz.

Regards,
John

 

[linnix]

Hi,

So, I need customized hardware to do this. Are you guys sure that
there are no chips available to do what I want to do? Any suggestions
or pointers that how should I proceed. I have FPGA generated clock and
data stream . Data is 48 bits wide and I am serially outing the data
at 1.5MHz.

Regards,
John

So you are dealing with 1.5Mbps. In theory, 5.8GHz 802.11n can
handle it. But with all the overheads of channellings and routings,
it will not guarantee the data rate. Your FPGA would have to talk
ethernet/TCP/IP in this case. You can bump it up with Multi-
Transceivers as another poster suggested, but it will not be cheap.
Your best bet is to do a simple modulation/protocol at 5.8GHz.