Environmental Engineering Reference
In-Depth Information
where
is the response of
at the frequency
with an input of
unity amplitude at the frequency
The location of the input of
is specified by
d
.
vi)
Further from frequency reversal theorem, the aliasing transfer func-
tion from the
noise source at the frequency
to the output
at the frequency
denoted by
is obtained from
where
is the
order frequency component of the re-
sponse of
vii)
The transfer and aliasing transfer functions from other noise sources
to the same output of
N
can be obtained by substituting appropriate
vectors into (11.114) and (11.115), respectively. Since all noise
sources are assumed to be uncorrelated, the total output noise power
of
N
is obtained by summing up the contributions of all noise sources.
Eq.(11.116) reveals that for a given periodically switched linear cir-
cuit, once the location and type of the noise sources are known, the
power spectral density of the output of the circuit at a given base band
frequency can be computed efficiently by solving the adjoint network.
4.5 Numerical Examples
The first example is the the switched capacitor low pass filter shown in
Fig.11.29 with the value of the circuit elements given in Table 11.7. Only
the thermal noise of MOSFET switches is considered. Five different
input noise band widths, 250 kHz, 500 kHz, 1 MHz, 5 MHz, and 10
MHz were considered in analysis. This corresponds to the foldover of
50, 100, 200, 1000, and 2000 sidebands. The output noise power was
Search WWH ::
Custom Search