What signal source is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal?
The local oscillator of the transmitter
An external RF oscillator
The transmitter balanced mixer output
The attenuated RF output of the transmitter✓الإجابة الصحيحة
الشرح
The signal being examined is the transmitter's own RF output, so it goes to the vertical input, but it must be attenuated first because full transmitter output would destroy the oscilloscope input. Internal frequency-source and mixer signals are not the transmitted envelope.