Functions Performed by RF Mixers Configured with Double Balanced Diodes

Radio frequency mixers available in the form of double balanced diode type mixers have found their wide applications to not only add various signals at the same time, but also for multiplication together. Whenever this type of situation takes place, output displays multiplication of two different input signals, while signals present at new frequencies become equal to difference and sum frequencies thus produced.

According to senior professors of various top engineering colleges in India, double balanced mixers mainly suppress two different input signals present at output. In this manner, individuals can observe only difference and sum frequencies. Moreover, balancing technique associated with the mixer device plays major role in isolation of two different input signals from one another. This activity would present entry of signals from input circuitry of one component to output circuitry of other one, while the resultant signal leads to possibility of inter-modulation process.

In this case, you will find typical figures to show performance of the circuit, which include isolation present in between ports equal to about 25dB and conversion loss, as equal to difference between signal levels of input and out as equal to about 8dB. With the help of typical diodes, one input level supplied to the mixer on the port of local oscillator is equal to 1 volt RMS or about 13dBm into resistance of 50 ohms.

EC professors of top engineering colleges in India have further explained that the isolation takes place in between different ports increase when the circuit causes accurate matching of coils and allow perfect balance. In addition, it is essential to make sure about perfect matching of diodes. Often you have to select diodes very carefully to make sure about close match of their properties.

Now, in order to achieve optimum level of performance, one should make sure of matching source impedances associated with two different input signals and load impedances of output signals to obtain the required value of impedance.

Based on this fact, few experts also recommend for placing of small attenuators in suitable lines of mixer component. These are mostly available in the value of 3dB and even though, they decrease the actual level of signal; play significant role to boost overall performance delivered by the mixer.

Despite, experimenters can choose to construct these mixers; for large numbers of commercial equipment pieces, they are preferable in manufactured forms. These instruments are available with required development level and thereby, play major role in bringing performance optimization.

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Created on Dec 31st 1969 18:00. Viewed 0 times.

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