AD9854/PCBZ Analog Devices Inc, AD9854/PCBZ Datasheet - Page 13

• Manufacturer Part Number: AD9854/PCBZ
• Description: 300 MHZ QUADRATURE DDS SYN. Eval Board
• Manufacturer: Analog Devices Inc
• Series: AgileRF™r

Specifications of AD9854/PCBZ

• Main Purpose: Timing, Direct Digital Synthesis (DDS)
• Utilized Ic / Part: AD9854
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 10 to Figure 15 show the trade-off in elevated noise floor, increased phase noise (PN), and discrete spurious energy when the internal
REFCLK multiplier circuit is engaged. Plots with wide (1 MHz) and narrow (50 kHz) spans are shown. Compare the noise floor of
Figure 11 and Figure 12 with that of Figure 14 and Figure 15. The improvement seen in Figure 11 and Figure 12 is a direct result of
sampling the fundamental at a higher rate. Sampling at a higher rate spreads the quantization noise of the DAC over a wider bandwidth,
which effectively lowers the noise floor.
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CENTER 39.1MHz
CENTER 39.1MHz
CENTER 39.1MHz
Figure 11. Narrow-Band SFDR, 39.1 MHz, 50 kHz BW,
Figure 12. Narrow-Band SFDR, 39.1 MHz, 50 kHz BW,
Figure 10. Narrow-Band SFDR, 39.1 MHz, 1 MHz BW,
300 MHz REFCLK with REFCLK Multiplier Bypassed
300 MHz REFCLK with REFCLK Multiplier Bypassed
100 MHz REFCLK with REFCLK Multiplier Bypassed
100kHz/
5kHz/
5kHz/
SPAN 50kHz
SPAN 50kHz
SPAN 1MHz
Rev. E | Page 13 of 52
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CENTER 39.1MHz
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Figure 14. Narrow-Band SFDR, 39.1 MHz, 50 kHz BW,
Figure 15. Narrow-Band SFDR, 39.1 MHz, 50 kHz BW,
Figure 13. Narrow-Band SFDR, 39.1 MHz, 1 MHz BW,
30 MHz REFCLK with REFCLK Multiplier = 10×
30 MHz REFCLK with REFCLK Multiplier = 10×
10 MHz REFCLK with REFCLK Multiplier = 10×
100kHz/
5kHz/
5kHz/
SPAN 50kHz
SPAN 50kHz
SPAN 1MHz
AD9854