Question
My application uses two AD2S1210 (NUM 1 and NUM 2) simultaneously to decode two rotary resolvers. I am required to use only one AD2S1210 (NUM1) tooutput EXC signals to simultaneously drive two rotary resolver, while AD2S1210 (NUM2) EXC pin is floating.Two rotary resolver’s signals are sensed respectively, SIN1, COS1, SIN2, COS2. Now I found the phase of NUM1 chip’s EXC output signal and SIN1 ,COS1 is relatively stable, while the phase of NUM2 chip EXC signal and SIN2, COS2 phase can not be relatively stable, there will be drift betweenthem.I wonder whether there are ways to solve the problem? Whether the purpose of my application can be realized?Whether this phenomenon can be avoided, making the two chips EXC output signal phase relatively stable.
Answer
The AD2S1200 device can be used in application like this however care should be taken to synchronize both devices together. To do that both AD2S1200should be sourced with the same 8.192 MHz clock for example from DSP or FPGA and the reset signal should also be applied at the same time. When thesetwo recommendations are followed both devices are synchronized and therefore there shouldn’t be any phase issues between Excitation signals.