beautypg.com

Figure 2-11, Pll architecture for the ni 5401 for pci -12, Figure 2-12 – National Instruments PXI NI 5401 User Manual

Page 35: Pll architecture for the ni 5401 for pxi -12

background image

Chapter 2

Function Generator Operation

NI 5401 User Manual

2-12

www.natinst.com

Figure 2-11. PLL Architecture for the NI 5401 for PCI

Figure 2-12. PLL Architecture for the NI 5401 for PXI

You can frequency lock to an external reference clock source of 1 MHz and
from 5–20 MHz in 1 MHz increments. The PLL can lock to a signal level
of at least 1 V

pk-pk

.

Caution

Do not increase the voltage level of the clock signal at the PLL reference input

connector by more than the specified limit, 5 V

pk-pk

.

Note

If two or more NI 5401 devices are locked to each other using the same reference

clock, they are frequency locked, but the phase relationship is indeterminate.

80 MHz

Div/4

VCXO

Board Clock (Master)

RTSI Clock (Slave)

Master/Slave

RTSI

Switch

RTSI Bus

RTSI Osc

Board Clock

20 MHz

Loop
Filter

Tune

DAC

PLL Ref

(1 V

pk-pk

min)

Control

Voltage

(20 MHz)

Source

14

Phase

Comp

AMUX

80 MHz

Div/8

VCXO

PXI Bus

10 MHz

Loop
Filter

CAL

DAC

PLL Ref

(1 V

pk-pk

min)

Control

Voltage

10 MHz Osc

Source

Phase

Comp

AMUX