Most of us have experience using a wideband signal injection transformer to introduce a modulation signal into our loop stability test. While a high quality injection transformer, such as the Picotest J2100A or J2101A often provides more than adequate results, there areapplications where higher fidelity, lower noise and even wider bandwidth are required. This application note shows some applications that can benefit from the J2110A Solid State Injector, also sometimes referred to as a “Bode Box.”
A block diagram of the J2110A Solid State Injector is shown in Figure 1.
The J2110A provides a bandwidth of DC to more than 100MHz and is designed to have very low noise and very high linearity so that the oscillator (OSC) signal and the input are summed with minimal mixing products. This feature allows the J2110A to be used for IMD testing of audio, ultrasonic and other low frequency RF signals, in addition to higher fidelity measurements of control loops, such as in power supplies and opamp circuits.