Datasheet

AD9577 Data Sheet
Rev. 0 | Page 24 of 44
TYPICAL SPREAD SPECTRUM PERFORMANCE CHARACTERISTICS
100.1
100.0
99.4
99.5
99.6
99.7
99.8
99.9
FREQUENCY (MHz)
TIME (10µs/DIV)
09284-033
Figure 29. Typical Spread Spectrum Frequency Modulation Profile OUT2,
Nb = 96, FRAC = 0, MOD = 1000, CkDiv = 7, NumSteps = 59, FracStep = −8,
f
OUT
= 100 MHz with −0.5% Downspread at 30.2 kHz, MAX_BW set to 0
10
0
–10
–20
–80
–70
–60
–50
–40
–30
99.00 100.50100.25100.0099.7599.5099.25
POWER (dBm)
FREQUENCY (MHz)
UNMODULATED
CLOCK SPECTRUM
MODULATED
CLOCK
09284-034
Figure 30. Typical Nonspread and Spread Spectrum Power Spectra, OUT2,
Nb = 96, FRAC = 0, MOD = 1000, CkDiv = 7, NumSteps = 59, FracStep = −8,
f
OUT
= 100 MHz with −0.5% Downspread at 30.2 kHz, MAX_BW set to 0,
First Harmonic Shown, Spectrum Analyzer Resolution Bandwidth =10 kHz,
Maximum Hold On
0
–10
–20
–90
–80
–70
–60
–50
–40
–30
695 701699697
POWER (dBm)
FREQUENCY (MHz)
09284-035
Figure 31. Typical Nonspread and Spread Spectrum Power Spectra, OUT2,
Nb = 96, FRAC = 0, MOD = 1000, CkDiv = 7, NumSteps = 59, FracStep = −8,
f
OUT
= 100 MHz with −0.5% Downspread at 30.2 kHz, MAX_BW set to 0,
Seventh Harmonic Shown, Spectrum Analyzer Resolution Bandwidth =
120 kHz, Maximum Hold On