- 14 Problems 231
9.14 PROBLEMS
1 Viewed from the input port a four-terminal network consists of a series
impedance of 300 II followed by a shunt admittance of (1/900) S.
Determine (a) the z-parameters and (b) the y-parameters of the network.
2 A two-port T-network has a series resistance of 300 lI followed by a shunt
conductance of (1//900) S and then a series resistance of 600 lI. Determine
(a) the z-parameters and (b) the y-parameters of the network.
3 A transistor has the following h-parameters: hl~ = 1 kll; h~2 = 10-3;
h21 = 100; h22 = 10 .4 S. Using the equivalent circuit of Fig. 9.5 determine
(a) the voltage gain (V2/V1) and (b) the current gain (I2/I~) when a load
resistance of 1 klI is connected across the output terminals.
4 Determine the g-parameters of the transistor of Problem 3.
5 Each phase of a transmission line has a total series impedance of 95/75 ~ lI
and a shunt admittance of 1.04/90 ~ mS. Obtain the ABCD-parameters for
the nominal-Tr representation of the line.
6 A two-port T-network has series impedances Z~ = 2/60 ~ f~ and
Z2 = 5/-70 ~ ~ and a shunt admittance of 0.01/80 ~ S. Obtain the ABCD-
parameters for the line.
7 Five two-port networks consisting of a series resistance of 100 lI, a shunt
conductance of (1/400) S, a series resistance of 200 lI, a shunt conductance
of (1/400) S and a series resistance of 100 f~ are connected in cascade in
that order. Obtain the ABCD-parameters of the cascaded network.
8 A symmetrical-T four-terminal network has series resistances R~ and R2
each of 400 1~ and a shunt branch of resistance 600 1~. Determine the
characteristic impedance of the network.
9 Show that for non-symmetrical two-port networks the image impedances
are given by V/[(AB)/(CD)] and X/[(DB/CA)] where A, B, C and D are
the transmission parameters. [Hint: for each expression use the same
method as was used to obtain the expression Zo = X/(B/C), Equation
(9.63).110 If the resistor R 2 in Problem 8 is replaced with one of 600 ~ resistance,
determine (a) the ABCD-parameters of the new network and (b) the
image impedances Z~I and Z~2.
11 An attenuator pad has series resistances each of 200 ~ and a shunt
resistance of 800 ~ in a T-section. Calculate the insertion loss when it is
inserted between a load resistor of 1 k~ and a 30 V source having an
internal resistance of 1 k~.
12 The network of Problem 8 is inserted between a source and a load.
Determine the insertion loss if the resistance of the source and the load