"How does an impulse at the output of an IQ modulator translate into the baseband signals?"
I am going to interpret this question as: "What is the complex envelope of $s(t)$?", where $s(t)$ is gvien by:
$$\delta(t)\cos(2\pi f_c t)-\delta(t)\sin(2\pi f_c t)$$
Since the product of an impulse and a signal is mathematically a suspicious ...
The OP commented that he has practical reason he would like to pursue a simple bandpass equivalent of an impulse test. Here are some considerations with that in mind:
An impulse in time represents all frequencies, which will ultimately be band-limited by the channel. We could implement the IQ representation of the band-limited channel that could then be ...
fscanf(sensorInput, "%lf + j*%lf\t", &x[i]);
fscanf(sensorInput, "%lf,%lf\t", &x[i].real, &x[i].imag);
Notice that C++ provides complex type, they support the common complex operations, and provide an io, and they can read complex numbers writen as (1,3) directly file_in &...