Wavetek 147 Specifikace stáhnout pdf (Strana 108)

Field Sweeping with the SDA-5000: Considerations for Sweep in the Field

See Also

½ “Test Point Compensation Configuration” provides an

example of test point loss calculation (page 60).

CAUTION ! Setting the correct reverse sweep signal level

is critical to achieving accurate results without creating

interference for reverse path services.

In general, both the reverse telemetry and reverse sweep levels can be set

to the same value and system specs. For reliable operation, the reverse

telemetry frequency should have a S/N ratio of about 20dB. Higher levels will

produce more accurate readings, but you must be careful not to drive the

return path lasers or amplifiers into clipping. Lower levels might not provide

adequate S/N ratios for stable readings.

Setting the Sweep Direction

You can get to the reverse SWEEP screen (see Fig. 4-15) through the

NAVIGATOR or by pressing the SWEEP measurement mode key under

lower right corner of the screen. To be sure you’re at the reverse SWEEP

screen, hit the left diamond key. Use the up and down diamond keys to set

the direction to Reverse.

NOTE: Sweep direction is indicated in the upper right

hand corner of the Sweep screen. The letters FWD or REV

respectively represent a forward or reverse sweep in

progress. The two small arrows also indicate the sweep

direction. When they’re pointing right, a forward sweep is in

progress, and when they’re pointing left, a reverse sweep

is in progress.

NOTE: Many of the icons and other display features of the

reverse SWEEP screen are identical to those shown in Fig.

4-10.

Appendix C contains a list of the icons appearing in this

manual.

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Wavetek 147 Specifikace Strana 108