National Instruments 5441 用户手册

Figure 6.  Direct Path, 2-Tone Spectrum (Typical)

The noise floor in Figure 6 is limited by the measurement device. Refer to the 

Average Noise Density specifications.

Sources

1. Internal, Divide-by-N (N 

≥ 1)

2. Internal, DDS-based, High-Resolution

3. External, CLK IN (SMB front panel connector)

4. External, DDC CLK IN (DIGITAL DATA & 

CONTROL front panel connector)

5. External, PXI Star trigger (backplane connector)

6. External, PXI_Trig<0..7> (backplane connector)

Refer to the 

section for more 
information 
about internal 
clock sources.

0.0

25.0M

50.0M

75.0M

100.0M

125.0M

150.0M

175.0M

200.0M

–90.0

–80.0

–50.0

–70.0

–40.0

–60.0

–30.0

–20.0

–10.0

0.0

10.0

Frequency (Hz)

dBm