I am using an AD9789 in QDUC mode. It is fed with a digital I,Q signal rotating at -500kHz, the AD9789 upconverters it to 474.166MHz. As expected i observe a single CW at the output centered at 473.666 MHz.
The main parameters are :
* AD9789 clock is 2230MHz.
* I and Q digital amplitudes are at maximum, i.e. 0x4000.
* The sumscale and inscale gains are set to 1.0.
* Full scale output current is 20mA.
* Output schematics is the same as Figure 110 on page 56 of AD9789 datasheet rev. A.
The output level i expect is 50 Ohms x 20mA volts peak to peak, i.e. +4dBm.
The measurement only shows -10 dBm.
Why such a loss ? Is the expected value of +4dBm wrong ? Where are the lost dBms ?
Thanks to those who can help
PS : AD9789 Configuration sequence shown below : Adresse <- Data