Circuit Note

CN-0294

Rev. 0 | Page 3 of 5

Logic Level Measurement

In this example, the Rohde & Schwarz RTO1024 oscilloscope is

used together with two RT-ZS30 active probes to accurately

measure the high speed logic levels.

Install the ADF435x software to PC by doing the following:

1. Connect the EVAL-ADF4351EB1Z to the PC, follow the

hardware driver instructions as per UG-435.

2. Program the ADF4351 PLL as per the screenshot of the

ADF435x software (see Figure 3). In this example, an RF

frequency of 1 GHz is chosen.

3. Using two equal length short SMA cables, connect the

ADF4351EB1Z board to the CLK0/CLK0 SMA connectors

of the ADCLK948/PCBZ board.

4. Connect the differential output OUT2/OUT2 of the

ADCLK948/PCBZ to the high speed oscilloscope. See

Figure 4 for typical waveforms for a 1 GHz output.

Figure 3. ADF4351 Software Settings

Figure 4. ADCLK948 Oscilloscope Output for 1 GHz Logic Signal, Horizontal Axis: 200 ps/DIV, Vertical Axis: 200 mV/DIV