Measurement equations - help

Dear all,

I need help with this measurement equations (Y = output growth, S_I = Interest rate and PI = inflation).
The observable variables are ZZ_DY, ZZ_I and ZZ_PI. Which means these measurement equations? Could anyone help me ?

4*log(ZZ_DY) = S_DY;

ZZ_I-1 = S_I;

4*log(ZZ_PI) = S_PI;

Thanks a lot in advance.

Best Regards.

They are standard measeurement equations. See Pfeifer(2013): “A Guide to Specifying Observation Equations for the Estimation of DSGE Models”
The first and last one annualize output growth and inflation.
The second one maps the net interest rate in the model (S_I) to the gross interest rate in the data.

Thank you very much for your valuable help and prompt reply!