how can i multiply two signals using common componets?

[mosfets.bjt]

hi there,

i want to step up 100 khz frequency to 30 MHz by multiplying it by Abt 30 MHz frequency... can any one tell me any easy method to MULTIPLY TWO HIGH FREQUENCY SIGNALS upto 30 MHz using opamps , transistors or extremely common ics??

 

[smxx]

you have to build log and anti log amplifier. It so difficult.

 

[FvM]

you have to build log and anti log amplifier. It so difficult.

log-antilog analog mutipliers are of no use in frequency mixing.

Balanced mixers (diode quartetts or analog 4-quadrant multipliers) give the best performance and a considerable suppression of input signals, which is an important advantage, if the output frequency is near to one of the input frequencies. On the other hand, any non-linear component, e.g. a diode or transistor amplifier with sufficient drive signal can be used for frequency mixing. Balanced mixers with supplementing signal transformers are availiable as RF building blocks, e.g. from mini-circuits.com.

For 30 MHz, which isn't really a high frequency, an active balanced mixer (analog 4-quadrant multipliers) can be made from 6 individual transistors or diff-amp transistor arrays. Also CMOS analog switches can be used, if the 30 MHz carrier has a digital level.

 

[mosfets.bjt]

can u tell me how???

if u use op-amp it would be very easy for me to construct. because transistor thing requires too much passive components which makes the end circuit so messey

 

[FvM]

It's basically a nonlinear circuit and 30 MHz isn't the domain of typical common OPs.

As another point, even a perfect double balanced mixer generates two output frequencies f1+f2 and f1-f2. If f2 >> f1, as you intend, it's difficult to filter only one of the components.

In other words, I miss necessary specification details for a meaningful suggestion.