# Varying signal bandwidth with two signal generators

I would like to emulate a signal with bandwidth (like BPSK) for some testing, but the two signal generators I have access to do not have any BPSK options installed. If I know the frequency (2462MHz) and the bandwidth (16MHz) I want, is there a way to mock this up easily with two signal generators? I feel like this isn't a hard problem, but I am drawing a blank.

• Do you have any other equipment other than the signal generators? Do the generators have external modulation inputs (they often do)? – Jason R Mar 22 '13 at 15:02
• I can potentially scrounge some stuff up. It DOES have a EXT MOD1 INPUT (on both my sig gens actually), but it appears that it is only for AM, FM, PhiM though – toozie21 Mar 22 '13 at 15:42
• $\phi$M would refer to phase modulation, which is what you want. If you can scrounge up a function generator (really, anything that can generate a two-valued digital waveform) that meets the input specifications of the signal generator (read the manual), then you should be able to make something work. If you want a modulated bandwidth of ~16 MHz, see if you can generate an 8 Mbit/sec stream into the modulation input. – Jason R Mar 22 '13 at 15:46
• Would a square wave generator at 8MHz suffice? That seems like it would work, then I should be able to put it into the input select phase modulation and select A/C coupled external source, right? – toozie21 Mar 22 '13 at 16:13
• That could be used to generate a BPSK signal, but in order to get something that looks more like a real-world signal, you would want something that generates a pseudorandom modulating sequence. Modulating by a square wave will yield a signal with a line spectrum. You will also want to check the specifications on the external modulation input to see if there are any bandwidth limitations on the modulating signal. – Jason R Mar 22 '13 at 17:24