If the local oscillator signal was to enter the power amplifier and not be adequately suppressed then it could be radiated.

Another triode acted as a mixer by coupling the oscillator signal into the mixer's cathode, and the received signal to the grid.

Also keeping the oscillator signal out of the antenna circuit was difficult.

The British Broadcasting Corporation's television licensing group, for example, deploys so-called detector vans to drive down residential streets and detect oscillator signals from televisions inside homes.

Even if the input is binary, after sampling with the oscillator signal the signal is analog (due to the finite edge width).

The input weak signal is mixed with a strong local oscillator signal, and the resultant strong output is used in the ensuing receiver stages.

To guarantee a clean local oscillator signal to the Shottky diode mixer module 6 separate VCO's are being used.

For example, if the phase locked loop were to implement a frequency multiplier, the oscillator signal could be divided in frequency before it is compared to the reference signal.

The incoming signal and the local oscillator signal are applied to a demodulator circuit.

Signals are received and converted into audible form by using a product detector mixing the local oscillator signal with the received signal, very similar to Software-defined radio.