US 8,897,728 B2Granted

Method for memory effects quantification and comparison in RF transmitters and amplifiers

AssigneeKing Fahd University of Petroleum and Minerals

InventorOalid Hammi

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Abstract

The method for memory effects quantification and comparison in RF transmitters and amplifiers is a method in which a processor performs a spectrum analysis of an RF transmitter or RF amplifier device under test (DUT). The processor then calculates a normalized frequency (fn) according to the relation: f n = f - f c BW . The processor then utilizes the normalized frequency calculation in a spectrum asymmetry index (SAI) computation characterized by the relation: SAI = 1 K ⁢ ∑ f n = f n , start f n = f n , stop ⁢ ⁢  P ⁡ ( f n ) - P ⁡ ( - f n )  . Next, utilizing the absolute value of the normalized frequency according to the relation:  f n  =  f - f c BW  , the processor displays the calculated SAI and causes a display device to display a mirrored spectrum as a function of the absolute value of the normalized frequency around a zero frequency. The resulting plot and calculated SAI displays reveal the degree of memory effects a given DUT exhibits. Similarly produced display plots among various DUTs can be quantitatively compared utilizing the method's SAI metric.

Claims3

Dependent claims

A computer software product, comprising a non-transitory medium readable by a processor, the medium having stored thereon a set of instructions for quantifying memory effects and comparison in RF transmitters and amplifiers, the set of instructions including:

(a) a first sequence of instructions which, when executed by the processor, causes said processor to perform a spectrum analysis of an RF emitter device under test (DUT);
(b) a second sequence of instructions which, when executed by the processor, causes said processor to calculate a normalized frequency (fn) according to the relation:
f
n
=
f
-
f
c
BW
,
where f is the frequency in MHz, fc is the carrier frequency, and BW is the signal bandwidth in MHz;
(c) a third sequence of instructions which, when executed by the processor, causes said processor to calculate a spectrum asymmetry index (SAI) characterized by the relation:
⁢
A
⁢
⁢
I
=
1
K
⁢
∑
f
n
=
f
n
,
start
f
n
=
f
n
,
stop
⁢

P
⁡
(
f
n
)
-
P
⁡
(
-
f
n
)

,
where P(fn) is the power spectrum density of the measured output signal, fn is the normalized frequency, K is the number of frequency terms in the summation, and fn,start and fn,stop are the lower and the upper frequency bounds used for SAI calculation, respectively;
(d) a fourth sequence of instructions which, when executed by the processor, causes said processor to display the calculated SAI;
and
(e) a fifth sequence of instructions which, when executed by the processor, causes said processor to display a mirrored spectra comprised of said calculated SAI around a zero frequency utilizing the absolute value of said normalized frequency according to the relation:

f
n

=

f
-
f
c
BW

,
where fn is the normalized frequency, f is the frequency in MHz, fc is the carrier frequency, and BW is the signal bandwidth in MHz.

70 more elements

Dependencies are inferred from the claim text.