Frequency synthesizers are quite expensive especially for double conversion RF systems. Maybe there are cheaper solutions instead of VCO that might be not such precise. A while ago I was analyzing one repeater that was using RS485 driver for LO. Maybe you have similar experience and can suggest something. For double conversion two individual frequency synthesizers are required or is there any solutions to utilise single one (using) it harmonics or something more exotic. Thank you in advance
Hi Audrius Merfeldas ,
if you can get rid of the harmonics of digital signals in your application (as you had to when using an RS485 driver) then I would recommend Silicon Labs' Si5338 (please see the attached files).
It provides 4 output frequencies and a host of possibilities. For fixed frequencies (i.e. all register contents can be pre-calculated), any microcontroller will do for configuration. In applications with variable frequencies, a 32 bit microcontroller should be used because 64 bit precision is needed.
The hardware (Si5338 + microcontroller) is certainly much cheaper than any commercially available frequency synthesizer. The software for variable frequencies takes some working hours because it's quite a task to become acquainted with the 351 registers in the Si5338.
In a simple application with one variable frequency, I used a SAMS70J for calculating and transferring the register contents to the Si5338.
Thank you very much Joerg Fricke . Thats basically what I was searching for. If anybady have cheaper solution please feel free to share. Thank you in advance.
- Badges
- Science topic
- Similar topics
- Filing