National Instruments SCXI-1190/1191 Uživatelský manuál stáhnout pdf (Strana 36)

Appendix B Common Questions

SCXI-1190/1191 User Manual B-2 www.ni.com

One of my modules doesn’t switch properly anymore. What’s wrong?

One of the relays has probably worn out. Relays are mechanical devices

and have a limited switching lifetime. Call National Instruments for

information on replacing your relays.

What is VSWR, and how does it affect my system?

VSWR stands for Voltage Standing Wave Ratio; it is a measure of the

reflection on a transmission line. The percentage of a signal reflected back

to the source is equal to (VSWR-1)/(VSWR+1). This means that a VSWR

of 1 is optimum, with no reflected signal. On higher power applications, a

large VSWR can damage the output stage of the source. High VSWR also

means that a large percentage of the power from the source cannot be

delivered to the load.

What is isolation, and why is it important?

Isolation is a measure of the amount of cross-talk between channels. For

example, if a 1 Vp-p signal is isolated by 40 dB to another channel, then

10 mVp-p will be seen on the adjacent channel (in addition to the signal

already on the channel).

1 2 ... 31 32 33 34 35 36 37 38 39 40 41 ... 44 45

Žádné komentáře

National Instruments SCXI-1190/1191 Uživatelský manuál Strana 36