Modeling, Analysis, and Experimental Validation of Frequency Dividers with Direct Injection
(a) Nonlinear characteristics of the injection circuit shown in Figure 3(b) for different values of the constant injection voltage , obtained for and . Measurements are obtained using integrated circuits ST HCF4007UB and the testing circuit in Figure 4. Approximate model for is obtained using cubic polynomial (4) with , , and . (b) Voltage-dependent transconductance . Measurement’s curve is obtained using (2) and curves shown in (a). Approximate model is obtained using the last term in (4) with .