# Microwave Mixer Technology and ApplicationsRF Cafe Quiz #54

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This quiz is based on the information presented in Microwave Mixer Technology and Applications, by Bert Henderson and Edmar Camargo.

Graciously provided by Artech House

1.  What is the name given to a receiver circuit whose oscillator circuit is biased just shy of the oscillation point in order to increase signal sensitivity?

a)  Recyclable
b)  Single-balanced
c)  Double-balanced
d)  Regenerative

2.  What is the name given to a mixer configuration that cancels out received signal frequencies that are equidistant from the oscillator frequency as the intended signal, but on the opposite side of the oscillator; i.e., on the opposite equivalent sideband?

a)  Image reject
b)  Sideband reject
c)  Mirror reject
d)  Opposite reject

3.  What is Error Vector Magnitude (EVM)?

a)  The magnitude expected vector
b)  The magnitude of the measured vector
c)  The difference between the expected vector magnitude and the measured vector magnitude
d)  The sum of the expected vector magnitude and the measured vector magnitude

4.  What is a "cold FET?"

a)  A FET bathed in a cryogenic fluid
b)  Slang for a burnt-out FET
c)  An insensitive FET
d)  A FET circuit without DC bias

5.  Why might a Lange coupler be preferred over a 3 dB hybrid coupler?

a)  Lower insertion loss
b)  Higher power handling
c)  Wider bandwidth for impedance matching
d)  Narrower bandwidth for impedance matching

6.  What are mixer spurious products comprised of?

a)  Small signal LO and small signal RF inputs
b)  Small signal LO and large signal RF inputs
c)  Large signal LO and small signal RF inputs
d)  Large signal LO and large signal RF inputs

7.  Why does the mechanism of noise generation in a mixer differ than that of an amplifier?

a)  Because the device parameters vary in time in response to the LO signal
b)  Because of passive versus active operation
c)  Because diodes are noisier than transistors
d)  Because a two-port component is different than a 4-port component

8.  Why does a cascode amplifier provide higher gain than a single stage?

a)  Because of a higher bias current
b)  Because of a lower supply voltage requirement
c)  Because of higher output impedance and higher reverse isolation
d)  Because of its smaller physical size

9.  What is the equivalent of a triply-balanced mixer?

a)  A combination of three singly balanced mixers
b)  A combination of two doubly balanced mixers
c)  Three diodes in a star configuration
d)  Three diodes in a ring configuration

10.  What is a major advantage of the Gilbert cell topology?

a)  It has a much lower implementation cost
b)  It uses fewer components required
c)  It has a smaller circuit footprint
d)  It multiplies the input and output currents to avoid improve linearity

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