CMX971 Datasheet, PDF (18/25 Pages) CML Microcircuits – Small 16-lead VQFN Package

Quadrature Modulator
CMX971
8.2.2 Linearity
Typical linearity of the I/Q modulator using a two-tone test is shown in Figure 10 for -7kHz and +9kHz
tones with composite input levels of 0.5Vp-p and 1Vp-p on I and Q. The CMX971 variation in linearity with
frequency is shown in Figure 11 by means of the change in output third order intercept point (OIP3). The
results are measured with a two-tone signal (-7kHz and +9 kHz tones) with a composite input level of
500mVp-p.
For optimum intermodulation performance the F bits in the Control Register ($1E, b3-b0) should be set to
‘0000’, this condition is used in Figure 10 and Figure 11.
Figure 10 Linearity at 500 MHz, 1Vp-p and 0.5Vp-p Differential Input Levels
 2015 CML Microsystems Plc
18
D/971/4