3) Sin(x)/x rolloff is reduced over the effective bandwidth.

Figure 9 illustrates a practical example of the benefits

when using the MAX5895 in 2x, 4x, and 8x interpolation

modes with the third filter configured as a lowpass filter.

With no interpolation filter, the first image signal appears

interpolating filter removes this image. In fact, all of the

then passed to the second interpolating filter, which is

16-Bit, 500Msps Interpolating and Modulating

Dual DAC with CMOS Inputs

______________________________________________________________________________________

21

FOR COMPLEX MODULATION THE MODULATION SIGN (BIT 1, ADDRESS 01h) SELECTS UPPER OR LOWER SIDEBAND

LOWER

SIDEBAND

UPPER

SIDEBAND

FILTER

RESPONSE

FILTER

RESPONSE

INPUT

SPECTRUM

AND FIRST

FILTER

RESPONSE

OUTPUT

SPECTRUM

OF THE

FIRST

FILTER

INPUT

SPECTRUM

AND

SECOND

FILTER

RESPONSE

OUTPUT

SPECTRUM

OF THE

SECOND

FILTER

OUTPUT

SPECTRUM

OF THE

MODULATOR

2x INTERPOLATION

4x INTERPOLATION

NO INTERPOLATION

SIGNAL

IMAGE

SIGNAL

IMAGE

SIGNAL

IMAGE

SIGNAL

SIGNAL

IMAGE

IMAGE