Network analyzer using PIC 16f877a.

[demetal]

Hi,
I want to design a network analyzer using pic 16f877a with an interface to the computer to run a gui to display the results... For this i need your valuable suggestions...

Please help.

 

[shahbaz.ele]

what are the things you want to measure with this network analyzer
we have seen spectrum analyzer with PIC here https://hackaday.com/2011/01/08/pic-spectrum-analyzer-uses-fast-fourier-transform-routine/.
Network analyzer is a big thing.

 

[thylacine1975]

Hey demetal,

While the project sounds like a good idea, it might need to be scoped with a little more detail - it's like saying you want to build a racing car around a spark plug!

The 16F877A is a nifty controller, but even at this stage I'd be skeptical of its utility in a VNA design, primarily due to it's limited (RAM) memory. Since you'd probably want to store many sample points, configuration data etc, I'd opt for a micro with a greater dataspace... and in all honesty I'd probably reach for a DSP with an external memory interface. (Not to mention the '877's best "PC interface" is probably its UART. The PIC18F4550 features as many IO's and a USB interface to boot...)

The micro is an incidental part of the design though - the heart of a network analyser is in its reflection bridges, synthesisers, gain and phase measurement engines etc. I presume you're planning an RF design? (There are a few audio/LF designs on the 'net) What frequency range? Thanks to the wireless revolution, there's a bunch of RF IC's available that would make a low cost DC-2.5GHz design quite plausible.

Good luck!

 

[demetal]

Hi,

I am not sure about the design... but i want to measure the parameters related to RF like s-parameter , antenna design parameters etc. .... Is it possible...?

---------- Post added at 15:28 ---------- Previous post was at 15:18 ----------

Hey demetal,

While the project sounds like a good idea, it might need to be scoped with a little more detail - it's like saying you want to build a racing car around a spark plug!

The 16F877A is a nifty controller, but even at this stage I'd be skeptical of its utility in a VNA design, primarily due to it's limited (RAM) memory. Since you'd probably want to store many sample points, configuration data etc, I'd opt for a micro with a greater dataspace... and in all honesty I'd probably reach for a DSP with an external memory interface. (Not to mention the '877's best "PC interface" is probably its UART. The PIC18F4550 features as many IO's and a USB interface to boot...)

The micro is an incidental part of the design though - the heart of a network analyser is in its reflection bridges, synthesisers, gain and phase measurement engines etc. I presume you're planning an RF design? (There are a few audio/LF designs on the 'net) What frequency range? Thanks to the wireless revolution, there's a bunch of RF IC's available that would make a low cost DC-2.5GHz design quite plausible.

Good luck!

Ok. fine so can you please suggest me the controller which i can use for this purpose.... I dont want advanced measurement purpose... just using for micro strip antenna design analysis and for that 2.5GHz will do....

 

[thylacine1975]

Any one of Analog Devices/Texas Instruments DSP lineup would likely fit your bill. Navigating the development software and interfacing to them can be a non-trivial excerise though! Given your familiarity with the '877, I'd probably suggest one of the Microchip dsPIC family as a good way to go - they seem to offer a nice blend of numerical horsepower with IO convenience, all from within MPLAB

There's a couple of published VNA designs around that might provide some insipration:
http://www.realhamradio.com/n2pk-vna.htm
http://sdr-kits.net/DG8SAQ/VNWA/Baier_VNWA2_QEX.pdf

Although for lower-precision (i.e. minimal superheterodyne-type frequency translation steps) work at 2.4 GHz, this was more the type of device I had in mind:
http://www.analog.com/en/rfif-components/detectors/ad8302/products/product.html

Sounds like a cool project - enjoy!