Figure 2. M and N Divider Waveforms for Test Points 5 and 6

Figure 3. M and N Divider Waveforms for Test Points 1 and 2

The output of the IF Amplifier at U18 Pin 3 is at ECL logic levels: -0.9 V = high, -1.7 V = low. Typical voltage levels for Q3 and Q4 are shown in Table 1.

Table 1. IF Amplifier Voltage Levels

Voltage Levels

Q3 Q4

Emitter - 5 . 6 - 7 . 4

Base - 4 . 8 - 6 . 6

Collector 0 - 1 . 9

A7A3 5