ADJUSTMENTS

5-22. 3 dB BANDWIDTHADJUSTMENTS(SERIAL PREFIX l9O9A)(Cont'd)

3.Set signal level of 7.1 divisions on display with REF LEVEL FINE control. (Signal should be 0.9 division from top graticule line.)

4.Set RESOLUTION BW to 1 MHz and FREQ SPAN/DIV to 200 kHz. Adjust A9R85 LC to set band- width of 5 divisions at the fifth graticule line.

5 . Set RESOLUTION BW to 3 MHz and FREQ SPAN/DIV to 500 kHz. The bandwidth at the fifth graticule line should be between 5.4 and 6.6 divisions.

NOTE

A9R85 LC may be further adjusted to bring the 3 MHz and 300 kHz bandwidths within limits; however, the final measurement of the 1 MHz band. width must be between 4.5 and 5.5 divisions at the fifth graticule line. (If the 3 MHz bandwidth cannot be brought within limits by adjustment of A9R85 LC, change the value of factory-selected resistor A9R95*.)

6.Set RESOLUTION BW to 300 kHz and FREQ SPAN/DIV to 50 kHz. The bandwidth should be between

5.4and 6.6 divisions at the fifth graticule line. (If the bandwidth cannot be adjusted within the specified limits, change the value of factory-selectedresistor AgR89*.)

7.Set RESOLUTION BW to 100 kHz and FREQ SPAN/DIV to 20 kHz. The bandwidth should be between

4.3and 5.7 divisions at the fifth graticule line.

NOTE

If the 100 kHz bandwidth is not within the specified limits, change the values of factory-selectedresistors A13R19*, A13R43*, and A11R43*. If the bandwidth is too wide, increase the value of the resistors; if the bandwidth is too narrow, decrease the value of the resistors. The three factory-selected resistors need not be of equal value, but each must be within one standard value of the others.

8.Set RESOLUTION BW to 30 kHz and FREQ SPAN/DIV to 10 kHz. The bandwidth should be between 2.6 and 3.4 divisions at the fifth graticule line.

NOTE

If the 30 kHz bandwidth is not within the specified limits, change the values of factory-selectedresistors A11R23*, A11R48*, A13R23*, and A13R48*. If the bandwidth is too wide, decrease the value of the factory-selectedresis- tors; if the bandwidth is too narrow, increase the value of the resistors. The four factory-selectedresistors need not be of equal value, but each must be within one standard value of the others.

9.Connect signal generator through the BNC Tee connector to the step attenuator and to the frequency counter as shown in Figure 5-8. Set the signal generator to approximately 0 dBm and the step attenuator to 30 dB.