Wobbulator

A wobbulator is an electronic device primarily used for the alignment of receiver or transmitter intermediate frequency strips. It is usually used in conjunction with an oscilloscope, to enable a visual representation of a receiver's passband to be seen, hence simplifying alignment; it was used to tune early consumer AM radios. The term "wobbulator" is a portmanteau of wobble and oscillator. A "wobbulator" (without capitalization) is a generic term for the swept-output RF oscillator described above, a frequency-modulated oscillator, also called a "sweep generator" by most professional electronics engineers and technicians. A wobbulator was used in some old microwave signal generators to create what amounted to frequency modulation. It physically altered the size of the klystron cavity, therefore changing the frequency.