Ross VEA-8707A, Руководство пользователя

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3–2 • User Controls VEA-8707A User Manual (Iss. 01)
Card Overview
This section provides a general overview of the VEA-8707A components. For information on the
LEDs available on the card-edge, refer to the section ““
Control and Monitoring Features ” on
page 3-4.
Figure 3.1 VEA-8707A — Components
1. Gain Adjustment (RV1)
Use RV7 to adjust the gain as required for your system and cable length. Use any suitable test
signal that would enable the signal gain and sub carrier level to be correctly set (e.g. pulse and bar
or color bar). A sweep signal can be used, but is not normally required.
2. Delay Adjustment (CV1)
The CV1 delay adjustment is factory-set to ensure than the path length of every VEA-8707A is
precisely matched. The VEA-8707A is factory-calibrated to have a delay of 26ns. This allows for
maximum interchangeability of cards without affecting system timing. Changing from the factory
setting will make this card non-interchangeable due to differences in delay. However, if desired,
and interchangeability is not important, the timing adjustment
CV1 may be used to resolve minor
system timing problems. CV1 has a typical range of ± 1.6ns.
3. EQ Adjustment (RV2)
Use RV2 to offset any frequency losses resulting from the coaxial cable. Adjust for proper burst
amplitude.
4. Input Signal LEDs
The front card-edge of the VEA-8707A has LED indicators that indicate the status of the input
signals. Refer to the section “
Status and Selection LEDs on the VEA-8707A ” on page 3-4 for
details.
5. Bootload Button (SW3)
This button is used for factory service in the unlikely even of a complete card failure. Refer to the
section “
Bootload Button ” on page 6-2 for details on the bootload process.
6. Cable Type Selection (JP6 and JP7)
Use JP6 and JP7 in conjunction to select the input cable type being equalized. The two jumpers
must both be positioned at only of the following selections:
1) Gain Adjustment ( RV1 ) 5) Bootload Button ( SW3 ) 9) Input Coupling ( JP1 and JP2 )
2) Delay Adjustment ( CV1 ) 6) Cable Type Selection ( JP6 and JP7 ) 10) Local Termination Jumper ( JP8 )
3) EQ Adjustment ( RV2 ) 7) Clamping Speed Selection ( JP3 )
4) Input Signal LEDs 8) Back Porch Clamping ( JP4 )
Note
— For other cable types, select the closest option from the provided list.
1
2
3
5
4
6
7 8
9
10