You will have to make even more adjustments, since U3 also needs an offset at its input because of having only a positive supply.
And also the driving voltage of +/- 1.2Volt is way too large since overall gain is 10x.
Using +/- 0.2Volt instead, will result in +/- 4V out or 8Vpp.
To create the proper 7.5V offset for U3, the DC offset for U1 and U2 will have to differ 7.5V/10 = 0.75Volt.
The two Sine voltages will now be:
Sine (7.5 0.2 1000) and Sine (6.75 -0.2 1000)
When however you add a negative supply for all op-amps, you can forget about DC offset voltages, and U3 will produce an output with a DC voltage of 0Volt.
Hans
And also the driving voltage of +/- 1.2Volt is way too large since overall gain is 10x.
Using +/- 0.2Volt instead, will result in +/- 4V out or 8Vpp.
To create the proper 7.5V offset for U3, the DC offset for U1 and U2 will have to differ 7.5V/10 = 0.75Volt.
The two Sine voltages will now be:
Sine (7.5 0.2 1000) and Sine (6.75 -0.2 1000)
When however you add a negative supply for all op-amps, you can forget about DC offset voltages, and U3 will produce an output with a DC voltage of 0Volt.
Hans