Method for enlarging the interference-free dynamic range of non-linear signal processing components
A method for enlarging the interference-free dynamic range of non-linear signal-processing components in receiver systems, in the conversion of input frequencies f in into output frequencies f out . According to the invention, at least one linear combination of at least one input frequency f in,t , f in,b and a fixed, predetermined oscillator f LOn of the components is calculated from the output signal of the component, for at least one output frequency f out,s , f out1,s , f outs,2 , which combination is compared with any desired output frequency f out,t of the component, whereby the output frequency f out,s , f out1,s , f outs,2 is then recognized as a spur and eliminated from the output signal of the component, if the calculated linear combination corresponds to any desired output frequency f out,t of the component, within a frequency and power range that can be predetermined.
1. A method for enlarging an interference-free dynamic range of non-linear signal-processing components in receiver systems, in the conversion of input frequencies f in into output frequencies f out , comprising:
calculating at least one linear combination of at least one input frequency f in,t , f in,b and a fixed, predetermined oscillator f LOn of the components from an output signal of the component, for at least one output frequency f out,s , f out1,s , f outs,2 ;
comparing said combination with any desired output frequency f out,t of the component;
recognizing an output frequency f out,s , f out1,s , f outs,2 as a spur; and
eliminating said output frequency recognized as a spur from the output signal of the component, if the calculated linear combination corresponds to any desired output frequency f out,t of the component, within a predetermined frequency and power range.
2. A method according to claim 1 , wherein the output frequencies f out,s , f out1,s , f outs,2 to be checked are sorted in the output signal according to their power, in ascending or descending order.
3. A method according to claim 1 , wherein the linear combination that can be predetermined is a linear combination of mixer harmonics.
4. A method according to claim 2 , wherein the original input frequency f in,b ahead of a signal-processing, non-linear component is calculated for each output frequency f out,s of the output signal to be checked.
5. A method according to claim 4 , wherein linear combinations are calculated for the output frequency f out,s according to
f
out
,
s
z
=
A
·
f
i
n
,
b
+
∑
n
=
1
N
B
n
·
f
LOn
with
A, B n : parameters that can be predetermined, with A, B n εZ,
f in,b : input frequency ahead of the non-linear component,
f LOn oscillator frequency of an n th stage of the non-linear component,
N: number of stages,
z: running variable of the calculated linear combination.
6. A method according to claim 2 , wherein the linear combination that can be predetermined is a linear combination of intermodulations.
7. A method according to claim 6 , wherein the output frequency f out,b is calculated with a linear combination according to
f
out
,
b
z
=
C
A
f
i
n1
,
s
+
∑
n
=
1
M
x
(
n
)
·
f
LOn
±
B
f
i
n2
,
s
+
∑
n
=
1
M
x
(
n
)
·
f
LOn
+
∑
n
=
M
+
1
N
x
(
n
)
·
f
LOn
with
A, B, C: parameters that can be predetermined, with A, BεZ,
f in1,s : first input signal ahead of the component,
f in2,s : second input signal ahead of the component,
f LOn : oscillator frequency of an n th stage of the non-linear component,
N: number of stages of the non-linear component,
M: position of the non-linear component to be checked,
x(n): function that can be predetermined, with values +1 and −1,
z: running variable of the calculated linear combination.