MW_Radiolink _base band_

[Bob60]

Hello!
Does any body has idea concerning 4FSK base band realization for data transmuting.
Main parameters: full or semi duplex? data whitening, programmable bandwidth, up to 20 MHz and data transmitting speed up to 20-30Mb/s and Ethernet interface. Probably not so big deal, I hope so.

 

[jiripolivka]

There have been many such microwave radios made and installed. What new you need to introduce? What are your specifications?
Programmable bandwidth is possible but IF filters should match RF spectrum. Switched filters or DSP may be needed.

 

[Bob60]

Thanks for reply. I`m confident. More than ten years ago I quite successfully participate at same projects and we finally made own baseband on Spartan FPGAs . Now it`s same problem, but configuration should be little bit different. Ethernet interface and semi duplex RX-TX like WiFi protocol, because front-end works at one frequency, without duplex space and not so big speed direct conversation receiver with IF within 10-20MHz. IMHO it enough for 20-30Mb/s traffic.
Today all specialists are gone stay managers only, that is the reason why I ask you.
Otherwise nothing new. Simply frontend for modulation has only VCO input for FSK staff.

 

[jiripolivka]

Thanks for reply. I`m confident. More than ten years ago I quite successfully participate at same projects and we finally made own baseband on Spartan FPGAs . Now it`s same problem, but configuration should be little bit different. Ethernet interface and semi duplex RX-TX like WiFi protocol, because front-end works at one frequency, without duplex space and not so big speed direct conversation receiver with IF within 10-20MHz. IMHO it enough for 20-30Mb/s traffic.
Today all specialists are gone stay managers only, that is the reason why I ask you.
Otherwise nothing new. Simply frontend for modulation has only VCO input for FSK staff.

After your explanation I do not feel an expert. I have developed many mm-wave radios, mostly just the mm-wave parts. Customers delivered their IF, baseband etc. blocks.
Now most of those baseband devices are DSP where all modifications are easy. The only quantity that needs to be set is the IF bandwidth, to keep SNR high. With FSK, also phase noise is important, more at higher mm-wave bands.

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If you are interested, I have developed fast ASK modulators and detectors with which our company made mm-wave radios with up to 5 GB/s data rate. I have been surprised not many customers were interested though in the news record data rates were climbing slowly over 5...10 Gb/s.

 

[Bob60]

After your explanation I do not feel an expert. I have developed many

If you are interested, I have developed fast ASK modulators and detectors with which our company made mm-wave radios with up to 5 GB/s data rate. I have been surprised not many customers were interested though in the news record data rates were climbing slowly over 5...10 Gb/s.

Yes its very interesting. That is for LASER modulator?
As for baseband it has DSP configuration. FPGA core and DAC & ADC. Simply it was cheaper against real DSP.

 

[jiripolivka]

Yes its very interesting. That is for LASER modulator?
As for baseband it has DSP configuration. FPGA core and DAC & ADC. Simply it was cheaper against real DSP.

Yes, the first design was used at 1.25 Gb/s in an optical Ethernet, with lasers at 42-46 GHz. Other designs achieved ~5 Gb/s in short-range radios, at 28 and 60 GHz. ASK capability is >15 GHz at the IF or baseband, only the demand is missing.

If you can generate baseband signals, then they can be applied to MMIC FSK modulators and demodulators, e.g. made by Hittite.

 

[Bob60]

Nice. What about cost and how it looks. 60GHz is actually as well for me. Front end with patch antennas almost are ready.

 

[Bob60]

Yes, the first design

That is my design @ 24GHz with patch antennas RX & TX on board. On the picture you can see top and bottom of the front end module. Base band is quite actually. Where I can see your base band solution.

 

[jiripolivka]

For a similar system I used up-and down-converting mixers. Their IF ports are 50 Ohms and IF bandwidth extends from DC to 15 GHz, so any baseband can be applied. What do you need more to know?