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390 3. Reference Manual
The fourth argument of ApproximateTransferFunction denotes the maximum coefficient
error. It does not constitute a bound on the absolute error of a transfer function. The
absolute error may be larger or lower than the maximum coefficient error.
See also: ApproximateMatrixEquation (Section 3.11.3).
Examples
Below, we approximate the transfer function of the common-emitter amplifier.
maximum error of in all coefficients of powers of the complex frequency s.
Load Analog Insydes. In[1]:= AC,
Scope −> Global,
Ports −> {B, C, E},
Parameters −> {Rbe, Cbc, Cbe, beta, Ro,
RBE, CBC, CBE, BETA, RO},
Definition −> Netlist[
{CBE, {B, E}, Symbolic −> Cbe, Value −> CBE},
{RBE, {X, E}, Symbolic −> Rbe, Value −> RBE},
{CBC, {B, C}, Symbolic −> Cbc, Value −> CBC},
{CC, {B, X, C, E},
Symbolic −> beta, Value −> BETA},
{RO, {C, E}, Symbolic −> Ro, Value −> RO}
]
]
] // ExpandSubcircuits;
In[3]:= ceamplifier =
Circuit[
Netlist[
{V1, {1, 0}, 1},
{V0, {6, 0}, 0},
{C1, {1, 2}, Symbolic −> C1, Value −> 1.0*^−7},
{R1, {2, 6}, Symbolic −> R1, Value −> 1.0*^5},
{R2, {2, 0}, Symbolic −> R2, Value −> 47000.},
{RC, {6, 3}, Symbolic −> RC, Value −> 2200.},
{RE, {4, 0}, Symbolic −> RE, Value −> 1000.},
{C2, {3, 5}, Symbolic −> C2, Value −> 1.0*^−6},
{RL, {5, 0}, Symbolic −> RL, Value −> 47000.},
{Q1, {2 −> B, 3 −> C, 4 −> E},
Model −> BJT, Selector −> AC,
CBE −> 30.*^−12, CBC −> 5.*^−12, RBE −> 1000.,
RO −> 10000., BETA −> 200.}
]
]
Out[3]= Circuit