QUESTION

Question

Hi,

I was planning to design in the M10578-A3 (or similar) to discipline a 10MHz OCXO.  Unfortunately my design has a 1600MHz signal used throughout the product.  While this signal would not be deliberately routed to the PCB containing the GPS module, it would of course always be present at a low level.  Probably the lowest I could guarantee the 1600MHz signal would be -80dBm, and even that would take some doing.

It appears this is in-band to the SAW filter and LNA, which would seem to generally preclude the use of a GPS receiver in this product at all.  While I see "AIC, Active Interference Cancellation" referred to in the datasheet I have no idea if this is any help for my application.

Answer 1

Hi,

To prevent this signal effecting the GNSS module you should ensure you fit the recommended filter components as shown on page 8 for the reference schematic in the M10578-A3 product specification. 

with regards to your 1600MHz signal you should keep this internal to the PCB as much as possible and create a PCB layout with a stack up based on the below (4 layer example) to help mitigate any radiated noise.