A circuit that combines two or more signals is called a mixer. In this lab, your goal is to build a mixer that combines the signals generated by two voltage sources, V1 and V2, where:

V1 is a 1 kHz square wave that varies between 0V and +1V, and

V2 is a 5 kHz sine wave that varies between -1V and +1V.

Please design a circuit that mixes V1 and V2 to produce Vout such that

Vout≈12V1+16V2.
The resulting output should be similar to that shown in Figure 1. The maximum value of the output is approximately 667mV and the minimum value is approximately −167mV.

Question

A circuit that combines two or more signals is called a mixer. In this lab, your goal is to build a mixer that combines the signals generated by two voltage sources, V1 and V2, where:

V1 is a 1 kHz square wave that varies between 0V and +1V, and

V2 is a 5 kHz sine wave that varies between -1V and +1V.

Please design a circuit that mixes V1 and V2 to produce Vout such that

Vout≈12V1+16V2.
The resulting output should be similar to that shown in Figure 1. The maximum value of the output is approximately 667mV and the minimum value is approximately −167mV.

anonymous · Answer

I built a circuit with two voltage diveders one for V1 and one for V2, the wave is ok but the current doesn't match, instead of being from -167 mV to 667 mV is like from -67 to 367, but if I check the voltages without connecting at the final output, they seems to be ok. The fist square wave from 0 to 500 and the sinewave from -167 to 167...why?

kenljw · Answer

Hard to tell without circuit, things to check
The bandwidth required of a squareware is at least 5 times funamental, in your case 5KHZ
Your mixing with a 5KHZ sinewave, therefore uning above you must be able to a bandwidth of  5KHz +_ 5KHz ie at least 10 KHz
Using Nyquest criteria of twice the highest frequency, I would ensure the bandwith is 20Khz
You say the problem occurs when adding load, therefore check bandwidth of load and when loading.