What is the product detector?
The product detector is an electronic circuit that brings a message from a carrier modulated by amplitude or one side (SSB). It is based on a mathematical model of a report translated into a frequency domain by a quantity known as the frequency of the carrier frequency (RF). The product detector may or may not use the frequency blender to restore a message from a modulated or modified carrier.
In communication circuits, there is a message that can be combined, combined or used to modulate the RF carrier. The carrier envelope then becomes an attribute of the carrier that carries the original message. A envelope detector or demodulator is used to restore the message called modulation. In the amplitude modulation (AM) a simple diode detector corrects the carrier to form a direct current (DC) with an average level that is proportional to the original message. In the SSB, the product detector, along with other circuits, will reconstruct a message when only one of the two side bands is available.
It is possible to amplify the incoming RF once in the AM radio receiver and then feed the result to the frequency blender along with the local oscillator equal to incoming frequency. The output of the frequency blender will have several significantly strong outputs. The frequency range of the message will be available to the signal available at the mixer output. In addition, there will be other products such as a frequency signal equal to the sum of the incoming RF and the local oscillator. If the mixer filter only transmits a message, only the envelope detector will be obtained, which is a simplified product detector.
A simple product detector can be implemented using four diodes in a circuit similar to a gate circuit. When one of the two input signals is on 0 volts (V), missing diode distortion to get the second input to reach the output. The resulting signal is the product domain product that resultsor the basic zone. This is the original message.
in AM, RF carrier and both side zones are available in the carrier. One technique used in saving strength and bandwidth is the use of SSB. In the SSB transmitter, the output does not have a carrier and one of the side bands. When the SSB carrier is transmitted to the air and accepted, it is easy to notice when the accepted SSB sound turns the sound similar to the duck, while the resulting message will tend to move at the audio frequency. One option is to equip the SSB receiver with a very accurate and stable reference to the carrier frequency so that the product detector can demodulate the message by minimal distortion in terms of phase and frequency.