9.37 This problem explores the linearization of the transfer characteristics of the differential pair achieved by including emitter-degeneration resistances Re in the emitters (see Fig. 9.17). Consider the case I = 200 μA with the transistors exhibiting vBE = 690 mV at iC = 1 mA and assume α 1. (a) With no emitter resistances Re, what value of VBE results when v id = 0? (b) With no emitter resistances Re, use the large-signal model to find i C1 and iC2 when vid = 20 mV. (c) Now find the value of Re that will result in the same iC1 and i C2 as in (b) but with vid = 200 mV. Use the large-signal model.(d) Calculate the effective transconductance Gm as the ratio of the difference current, (iC1 − iC2), to vid in the cases without and with the R e’s. By what factor is Gm reduced? How does this factor relate to the increase in v id? Comment.