User's Manual

YTO

PLL7

/ROLLER OSCILLATOR PLL

1ST

LO OUTPUT

3.0

6.81 GHz

YTO

OFFSET LOCK

LOOP?

MHz TCXO

SK168

Figure 6-5. Phase Lock Loops

Roller Oscillator PLL (P/O A14)

This PLL’s output serves as the reference frequency for the YTO PLL. A one-to-one

relationship in frequency tracking exists between the Roller Oscillator PLL and the YTO.

(A change of 1 MHz in the Roller Oscillator PLL will produce a 1 MHz change in the YTO

frequency.)

The Roller Oscillator PLL actually contains three PLLs that collectively produce an output

of 63 MHz to 105.5 MHz. The three PLLs are the Main Roller PLL, Offset Roller PLL, and

Transfer Roller PLL.

The Offset Roller PLL tunes from 189 MHz to 204 MHz. Because the output of the PLL is

divided by 100, a one-hundred-to-one relationship exists between frequency changes in the

Offset Roller PLL and the YTO. The Offset Roller PLL can be synthesized in 2.5 kHz steps,

yielding an effective frequency resolution on the YTO of 25 Hz.

The Transfer Roller PLL tunes from 61 MHz to 103.5 MHz in 50 kHz steps.

IF Section

The IF Section processes the 10.7 MHz output of the RF Section and sends the detected video

to the ADC/Interface Section. The following major assemblies are included in this section:

A3 Interface assembly

A4 Log Amplifier/Cal Oscillator assembly

A5 IF assembly

General Troubleshooting 6-39