U.S. patent application number 15/225782 was filed with the patent office on 2018-02-01 for method and system to calibrate phase supported by factory trim data.
The applicant listed for this patent is NXP B.V.. Invention is credited to Gernot Hueber, Ian Thomas Macnamara.
Application Number | 20180034622 15/225782 |
Document ID | / |
Family ID | 59501205 |
Filed Date | 2018-02-01 |
United States Patent
Application |
20180034622 |
Kind Code |
A1 |
Hueber; Gernot ; et
al. |
February 1, 2018 |
METHOD AND SYSTEM TO CALIBRATE PHASE SUPPORTED BY FACTORY TRIM
DATA
Abstract
The present invention provides for a method and system to
compensate phase offset caused by the IC (integrated circuit) by
making use of factory measurement stored as trim-data in the IC. In
the final customer product, the trim-data is mapped to the actual
platform environment such that the respective phase offset can be
compensated.
Inventors: |
Hueber; Gernot; (Linz,
AT) ; Macnamara; Ian Thomas; (Graz, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NXP B.V. |
Eindhoven |
|
NL |
|
|
Family ID: |
59501205 |
Appl. No.: |
15/225782 |
Filed: |
August 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B 5/0075 20130101;
H04B 5/0031 20130101; H04B 5/0062 20130101; H04B 17/21 20150115;
H04L 7/04 20130101; H04W 4/80 20180201; H04L 45/745 20130101; H04B
17/318 20150115 |
International
Class: |
H04L 7/04 20060101
H04L007/04; H04B 17/318 20060101 H04B017/318; H04L 12/741 20060101
H04L012/741; H04W 4/00 20060101 H04W004/00 |
Claims
1. A method for determining and applying phase offset to a Near
Field Communication (NFC) communications device that communicates
via inductive coupling, the method comprising: measuring a received
signal strength indicator (RSSI) value for the NFC communications
device that communicates via inductive coupling, wherein the RSSI
value corresponds to a field strength of inductive coupling; using
a platform specific mapping table to determine an index of phase
trim corresponding to the measured RSSI value for the NFC
communications device that communicates via inductive coupling;
using a reference phase trim data to determine a phase offset
corresponding to the index of phase trim; and applying the phase
offset to the NFC communications device that communicates via
inductive coupling; wherein the platform specific mapping table
maps each RSSI value to each own index of phase trim; wherein the
platform specific mapping table is the same for all NFC
communications device belonging to the same type of NFC
communications devices, wherein each individual NFC communications
device belonging to the same type of NFC communications devices
does not have its own individualized platform specific mapping
table.
2. The method of claim 1, wherein the reference phase trim data
maps each phase offset to each own index.
3. The method of claim 2, wherein the reference phase trim data is
measured and stored for each individual NFC communications device,
wherein each individual NFC communications device has its own
individualized reference phase trim data.
4. (canceled)
5. (canceled)
6. The method of claim 1, wherein the reference phase trim data is
stored in a protected memory area not accessible to a user.
7. The method of claim 6, wherein the user is a customer.
8. The method of claim 1, wherein the platform specific mapping
table is stored in an open memory area accessible to a user.
9. The method of claim 1, further comprising: determining a TX
(transmitter) phase setting; determining a customer phase offset;
and applying the phase offset, the TX (transmitter) phase setting,
and the customer phase offset to the NFC communications device.
10. The method of claim 9, wherein the TX (transmitter) phase
setting is a phase setting used for TX (transmitter) referenced to
a phase detected at RX (receiver), wherein the customer phase
offset is a phase offset that is considered a part to part
variation of customer boards due to matching network and
antenna.
11. The method of claim 10, wherein the customer phase offset is a
static value evaluated once in a customer production test.
12. A method for determining and applying phase offset to a Near
Field Communication (NFC) communications device that communicates
via inductive coupling, the method comprising: measuring a received
signal strength indicator (RSSI) value for the NFC communications
device that communicates via inductive coupling, wherein the RSSI
value corresponds to a field strength of inductive coupling; using
a platform specific mapping function to determine a variable of
phase trim corresponding to the measured RSSI value for the NFC
communications device that communicates via inductive coupling;
using a reference phase trim data to determine a phase offset
corresponding to the variable of phase trim; and applying the phase
offset to the NFC communications device that communicates via
inductive coupling,. wherein the platform specific mapping function
maps each RSSI value to each own variable of phase trim; wherein
the platform specific mapping function is the same for all NFC
communications device belonging to the same type of NFC
communications devices, wherein each individual NFC communications
device belonging to the same type of NFC communications devices
does not have its own individualized platform specific mapping
function.
13. The method of claim 12, wherein the reference phase trim data
maps each phase offset to each own variable.
14. The method of claim 13, wherein the reference phase trim data
is measured and stored for each individual NFC communications
device, wherein each individual NFC communications device has its
own individualized reference phase trim data.
15. (canceled)
16. (canceled)
17. The method of claim 12, wherein the reference phase trim data
is stored in a protected memory area not accessible to a user.
18. The method of claim 12, wherein the platform specific mapping
function is stored in an open memory area accessible to a user.
19. (canceled)
20. (canceled)
21. A method for determining and applying phase offset to a Near
Field Communication (NFC) communications device that communicates
via inductive coupling, the method comprising: measuring a received
signal strength indicator (RSSI) value for the NFC communications
device that communicates via inductive coupling, wherein the RSSI
value corresponds to a field strength of inductive coupling; using
a platform specific mapping table to determine an index of phase
trim corresponding to the measured RSSI value for the NFC
communications device that communicates via inductive coupling;
using a reference phase trim data to determine a phase offset
corresponding to the index of phase trim; and applying the phase
offset to the NFC communications device that communicates via
inductive coupling; and further comprising: determining a TX
(transmitter) phase setting; determining a customer phase offset;
and applying the phase offset, the TX (transmitter) phase setting,
and the customer phase offset to the NFC communications device.
22. The method of claim 21, wherein the TX (transmitter) phase
setting is a phase setting used for TX (transmitter) referenced to
a phase detected at RX (receiver), wherein the customer phase
offset is a phase offset that is considered a part to part
variation of customer boards due to matching network and
antenna.
23. The method of claim 22, wherein the customer phase offset is a
static value evaluated once in a customer production test.
Description
FIELD
[0001] The described embodiments relate generally to method and
system to calibrate phase in a near field communication (NFC)
system, and more particularly to method and system to calibrate
phase supported by factory trim data in a near field communication
(NFC) system.
[0002] BACKGROUND
[0003] The use of Near Field Communication (NFC) is becoming common
place in applications such as contactless payment systems, security
access systems, etc. A typical NFC based system consists of a NFC
reader Point of Sale terminal) and a NFC device, typically a NFC
enabled card or a mobile phone.
[0004] Furthermore, a NFC device typically can be configured for
either passive load modulation (PLM) or active load modulation
(ALM). While, ALM is typically more complex than PLM, components
for implementing ALM in a transponder (e.g., a mobile device) can
be more compact and, because the transponder utilizes a power
source to generate a magnetic field rather than just modulate a
magnetic field created by a reader, an ALM transponder can have
greater communication distance than a PLM transponder.
[0005] In order to perform a transaction using a NFC enabled device
and a NFC reader, the NFC enabled device is brought near the NFC
reader. The communication between the NFC enabled device and the
NFC reader may fail if the NFC reader fails to properly demodulate
the signal from the NFC enabled device. Such failures may occur if
the NFC enabled device is not properly aligned with the NFC reader
or if the NFC enabled device is not within a certain distance range
from the NFC reader.
[0006] Such failures and other issues can be significantly reduced
if there is tuning of the phase for active load modulation (ALM) in
a NFC enabled device. Furthermore, there is a need to be able to
calibrate the phase in production testing and handling. Therefore,
it is desirable to have methods and systems to calibrate phase
supported by factory trim data.
SUMMARY
[0007] The present invention provides for a method and system to
compensate phase offset caused by the IC (integrated circuit) by
making use of factory measurement stored as trim-data in the IC. In
the final customer product, the trim-data is mapped to the actual
platform environment such that the respective phase offset can be
compensated.
[0008] An important point of this invention is to create and store
the trim-data referenced to an artificial (virtual) platform and
the respective set of artificial (virtual) parameters. When the
actual calibration is applied in the customer environment, an
efficient and simple scaling of the real and actual system platform
parameters to the virtual trim-codes needs to be applied (e.g., by
scaling).
[0009] The present invention provides for a method for determining
and applying phase offset to a communications device that
communicates via inductive coupling, the method comprising: (a)
measuring a received signal strength indicator (RSSI) value for the
communications device; (b) using a platform specific mapping table
to determine an index of phase trim corresponding to the measured
RSSI value for the communications device; (c) using a. reference
phase trim data to determine a phase offset corresponding to the
index of phase trim; and (d) applying the phase offset to the
communications device.
[0010] In some embodiments, the reference phase trim data maps each
phase offset to each own index.
[0011] In sonic embodiments, the reference phase trim data is
measured and stored for each individual communications device,
wherein each individual communications device has its own
individualized reference phase trim data.
[0012] In some embodiments, the platform specific mapping table
maps each RSSI value to each own index of phase trim.
[0013] In some embodiments, the platform specific mapping table is
the same for all communications device belonging to the same type
of communications devices, wherein each individual communications
device belonging to the same type of communications devices does
not have its own individualized platform specific mapping
table.
[0014] In some embodiments, the reference phase trim data is stored
in a protected memory area not accessible to a user.
[0015] In some embodiments, the user is a customer.
[0016] In some embodiments, the platform specific mapping table is
stored in an open memory area accessible to a user.
[0017] In some embodiments, the method further comprises: (e)
determining a TX (transmitter) phase setting; (f) determining a
customer phase offset; and (g) applying the phase offset, the TX
(transmitter) phase setting, and the customer phase offset to the
communications device.
[0018] In some embodiments, the TX (transmitter) phase setting is a
phase setting used for TX (transmitter) referenced to a phase
detected at RX (receiver), wherein the customer phase offset is a
phase offset that is considered a part to part variation of
customer boards due to matching network and antenna.
[0019] In some embodiments, the customer phase offset is a static
value evaluated once in a customer production test.
[0020] The present invention also provides for a method for
determining and applying phase offset to a communications device
that communicates via inductive coupling, the method comprising:
(a) measuring a received signal strength indicator (RSSI) value for
the communications device; (b) using a platform specific mapping
function to determine a variable of phase trim corresponding to the
measured RSSI value for the communications device; (c) using a
reference phase trim data to determine a phase offset corresponding
to the variable of phase trim; and (d) applying the phase offset to
the communications device.
[0021] In some embodiments.sub.; the reference phase trim data maps
each phase offset to each own variable.
[0022] In some embodiments, the reference phase trim data is
measured and stored for each individual communications device,
wherein each individual communications device has its own
individualized reference phase trim data.
[0023] In some embodiments, the platform specific mapping function
maps each RSSI value to each own variable of phase trim.
[0024] In some embodiments, the platform specific mapping function
is the same for all communications device belonging to the same
type of communications devices, wherein each individual
communications device belonging to the same type of communications
devices does not have its own individualized platform specific
mapping function.
[0025] In some embodiments, the reference phase trim data is stored
in a protected memory area not accessible to a user.
[0026] In some embodiments.sub.; the platform specific mapping
function is stored in an open memory area accessible to a user.
[0027] The present invention further provides for a method for
determining and applying phase offset to a communications device
that communicates via inductive coupling, the method comprising:
(a) measuring a characteristic parameter for the communications
device; (b) using a platform specific mapping table or function to
determine an index or variable of phase trim corresponding to the
measured characteristic parameter for the communications device;
(c) using a reference phase trim data to determine a phase offset
corresponding to the index or variable of phase trim; and (d)
applying the phase offset to the communications device.
[0028] In some embodiments, the characteristic parameter is a
received signal strength indicator (RSSI) value, wherein the RSSI
value corresponds to a field strength of inductive coupling.
[0029] The present invention can also provide for a computer
program product encoded in a non-transitory computer readable
medium for determining and applying phase offset to a
communications device that communicates via inductive coupling, the
computer program product comprising: (a) computer code for
measuring a characteristic parameter for the communications device;
(b) computer code for using a platform specific mapping table or
function to determine an index or variable of phase trim
corresponding to the measured characteristic parameter for the
communications device; (c) computer code for using a reference
phase trim data to determine a phase offset corresponding to the
index or variable of phase trim; and (d) computer code for applying
the phase offset to the communications device.
[0030] The above summary is not intended to represent every example
embodiment within the scope of the current or future Claim sets.
Additional example embodiments are discussed within the Figures and
Detailed Description below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The described embodiments and the advantages thereof may
best be understood by reference to the following description taken
in conjunction with the accompanying drawings. These drawings in no
way limit any changes in form and detail that may be made to the
described embodiments by one skilled in the art without departing
from the spirit and scope of the described embodiments.
[0032] FIG. I shows a diagram of load modulation amplitudes versus
example phase configurations of a communications device under
different inductive coupling conditions, in accordance with some
example embodiments.
[0033] FIG. 2 shows a block diagram of a typical receiver with UQ
mixer, amplifier, filtering, A/D (analog-to-digital) converter and
a signal demodulator in the baseband, in accordance with some
example embodiments.
[0034] FIG. 3 shows a block diagram that provides an overview of
the method for calculating a phase, in accordance with some example
embodiments.
[0035] FIG. 4 shows the phase behavior of a system/IC (integrated
circuit), in accordance with some example embodiments.
[0036] FIG. 5 shows the phase behavior of a system/IC (integrated
circuit), as the field strength (H)/RSSI from the respective
platforms is mapped to an invariant reference input, in accordance
with some example embodiments.
[0037] FIG. 6 shows a block diagram that provides an overview of
the method for calculating a phase that uses a reference phase trim
data to determine a phase offset, in accordance with some example
embodiments.
DETAILED DESCRIPTION
[0038] Representative devices and methods according to the present
application are described in this section. These examples are being
provided solely to add context and aid in the understanding of the
described embodiments. It will thus be apparent to one skilled in
the art that the described embodiments may be practiced without
some or all of these specific details. In other instances, well
known process steps have not been described in detail in order to
avoid unnecessarily obscuring the described embodiments. Other
embodiments are possible, such that the following examples should
not be taken as limiting.
[0039] In the following detailed description, references are made
to the accompanying drawings, which form a part of the description
and in which are shown, by way of illustration, specific
embodiments in accordance with the described embodiments. Although
these embodiments are described in sufficient detail to enable one
skilled in the art to practice the described embodiments, it is
understood that these examples are not limiting; such that other
embodiments may be used, and changes may be made without departing
from the spirit and scope of the described embodiments.
[0040] Active load modulation (ALM) is state of the art for all
mobile NFC solution in the market. In one embodiment, ALM is an
actively sending of 13.56 MHz signal modulated according to
standards for Type A/B/F. This grants a huge benefit in generated
signal strength and allows for the use of smaller antennas by
fulfilling the required standards like NFC Forum, ISO 14443, EMVCo,
etc. with respect to load modulation amplitude parameter.
[0041] A dedicated initial phase can be defined for the card
response for all cases of ALM. The initial phase setting can be
used to optimize the load modulation amplitude as shown in FIG. 1
for different coupling positions shown as "110", "120", "130", and
"140". In FIG. 1, the x-axis can represent the initial phase
setting in degrees (i.e., phase of ALM versus TX CW (transmitter
carrier wave) signal phase). FIG. 1 shows the load modulation
amplitude peaking for some phase values. Therefore, in some
embodiments, the phase can be used to optimize the load modulation
amplitude.
[0042] There are many reference communication counterparts in the
field (and certification test) which are strongly amplitude
dependent, e.g. some FeliCa readers and older payment terminals.
For these readers, which are strongly amplitude dependent, it can
be shown that only a small range of phase results in a passing
communication. Therefore, adjusting the phase to optimize the load
modulation amplitude can be a great help for use with these
counterparts (e.g. some FeliCa readers and older payment
terminals).
[0043] The transmitter (TX) phase (phase relation from reader field
as seen on the RX and the phase of the carrier at the TX) of the
NFC system depends on multiple system and/or environmental
parameters/conditions (e.g., field strength, detuning/coupling
condition, antenna geometries, IC (PVT) (integrated
circuit--process, voltage and temperature), matching network
(topology, . . . ), protocol, data-rate, retransmission,
reconfiguration, timings, applications, etc.
[0044] The TX (transmitter) phase that can be used for a platform
is defined by a measurement campaign with multiple reader
terminals. There is a TX phase range that gives a passing
communication for all readers (as, for example, defined in
1017(Interoperability Test) certification
[0045] The main challenge for compensating the phase is to: [0046]
(1) Compensate the phase offset caused by the IC itself (which may
be function of PVT, input voltage level, etc.). (Note: IC denotes
integrated circuit. PVT denotes process, voltage and temperature.)
[0047] (2) Assess the input voltage level accurately such that the
compensation can be done. [0048] (3) The RSSI can be used to
quantify a relative input voltage level as it is an absolute
reference that depends on platform parameters such as the matching
network, antenna, reference node for the RSSI, RSSI trim, etc.
[0049] Although trim in the factory (ATE) can be done already for
the respective target customer platform, this might immediately
cause huge diversity in test programs (such as one per customer
platform) and render the logistics of ATE (automated test
equipment) production testing and handling of the ICs difficult if
not even impossible.
[0050] An important point of this invention is to create and store
the trim-data referenced to an artificial (virtual) platform and
the respective set of artificial (virtual) parameters. When the
actual calibration is applied in the customer environment, an
efficient and simple scaling of the real and actual system platform
parameters to the virtual trim-codes needs to be applied (e.g., by
scaling).
[0051] An embodiment of a typical receiver is shown in FIG. 2. The
receiver 200 comprises I/Q mixer 220, amplifier 230, filtering 240,
A/D converter 250, and a signal demodulator 260. The receiver
receives a RF input 210 to the I/Q mixer 220 and generates a BB
(baseband) output 270 from the signal demodulator 260.
[0052] FIG. 3 gives an overview of a method for calculating a
phase, in accordance with some example embodiments. There are
several contributors to a calibrated phase 370, which is finally
dialed into the system.
[0053] The initial phase setting 350 is the target programmed
phase. This is an absolute phase value.
[0054] The customer phase offset 360 is a phase offset that
considers part to part variation of customer boards due to matching
network, antenna, etc.--basically contributors outside the IC and
hence only known to the IC by this parameter. This is a static
value evaluated once in a customer production test.
[0055] RSSI 330 is the dynamically measured metric that is
equivalent to the input voltage level. As the actual input voltage
value depends on platform parameters and RSSI trimming, the RSSI
does not give the absolute NTRX voltage. Note that input voltage
level and in turn RSSI 330 is dependent on the field strength H
(310)
[0056] The system scaling factor 320 is a correction of the
platform RSSI to the absolute VRX voltage.
[0057] An important step is the correction of the RSSI by means of
the system scaling factor 320 to evaluate to the absolute VRX,
which in turn is used as an index to the phase trim data (or in
some embodiments, the phase trim table). Hence, the phase trim data
(or in some embodiments, the phase trim table) can be kept target
platform independent, while the platform dependency can be
addressed by the system scaling. In FIG. 3, phase trim data is
shown as Phase Trim ph.sub.ic(RSSI) 340.
[0058] FIG. 4 shows the phase behavior of the system/IC (which is
shown as an arbitrary shape in this example), which actually
depends on the input voltage Vin. However, on the platform (e.g.,
platform 1, platform 2, etc.) the input signal can be quantified by
field-strength or RSSI or some other characteristic parameter. In
FIG. 4, for platform I, field-strength is shown as H_1, while RSSI
is shown as RSSI_. For platform 2, field-strength is shown as H_2,
while RSSI is shown as RSSI_2.
[0059] FIG. 5 shows the phase behavior of a system/IC (integrated
circuit), as the field strength (H)/RSSI from the respective
platforms is mapped to an invariant reference input, in accordance
with some example embodiments. In FIG. 5, the field-strength
(H_i)/RSSI (RSSI_i)/ . . . from the respective platform i has been
mapped to an invariant reference input H_ref/RSSI_ref. In
particular, field-strength H_1/RSSI_1 is associated with platform
1. Field-strength H_2/RSSI_2 is associated with platform 2.
Field-strength H_ref/RSSI_ref is associated with an invariant
reference platform. In other word, in FIG. 5, the phase behavior of
the IC/system is referenced to a virtual reference scale in terms
of field-strength/RSSI, which in turn is used as basis, which the
platform metrics (H, RSSI) is mapped to.
TABLE-US-00001 TABLE 1A Reference Platform 1 Platform 2 Phase Phase
Phase H_ref Offset H_ref Offset H_ref Offset (A/m) (deg) (A/m)
(deg) (A/m) (deg) 1 phi_1 1.1 phi_1 0.75 phi_1 2 phi_2 2.2 phi_2
1.5 phi_2 3 . . . 3.3 . . . 2.25 . . . 4 4.4 3 5 5.5 3.75 6 6.6 4.5
7 7.7 5.25 8 8.8 6 9 9.9 6.75 10 11 7.5
TABLE-US-00002 TABLE 1B Reference Platform 1 Platform 2 Phase Phase
Phase RSSI Offset RSSI Offset RSSI Offset (--) (deg) (--) (deg)
(--) (deg) 100 phi_1 110 phi_1 75 phi_1 200 phi_2 120 phi_2 150
phi_2 300 . . . 130 . . . 225 . . . 400 140 300 500 150 375 600 160
450 700 170 525 800 180 600 900 190 675 1000 200 750
[0060] In Table 1A and 1B, the phase offsets phi_1, phi_2, . . .
are referred to different field-strength/RSSI depending on the
actual platform. Table 1A and 1B show the mapping between phase to
be compensated (phi_i) and the respective parameter to be selected
(i.e., field strength H for Table 1A and RSSI for Table 1B). Note
that the values are examples only for illustrative purposes.
[0061] The important point is that the input to the mapping (e.g.,
field-strength, RSSI) is different from platform to platform and to
the reference. This variation can be overcome by adjusting the
input parameters according to the reference. This is inflexible and
undesirable.
TABLE-US-00003 TABLE 2 Reference Platform 1 Platform 2 Phase Index
of Index of Offset H_ref phase H_ref phase ID (deg) (A/m) trim
(A/m) trim 0 phi_1 1 0 1 0 1 phi_2 2 1 2 2 2 . . . 3 2 3 3 3 4 3 4
4 4 5 4 5 6 5 6 4 6 7 6 7 5 7 8 7 8 6 8 . . . 8 9 7 9 9 10 8 10
[0062] The approach is to use a mapping table (or function) as
shown in Table 2. This function allows for the use of the same
scale for the input (in this example in terms of field-strength,
but in another embodiment it could be RSSI as well) or an arbitrary
scale. The important part of the mapping table is that the scale
per platform maps (tabular or function) to the index of the actual
trim-table (the reference table).
[0063] Consequently, the mapping that needs to be defined per
platform no longer needs to contain any phase data, since that has
been moved into the reference table. The reference table, in turn,
can be considered as a trim-data table that is filled with data
during a factory test (of the IC) and is fully separated and
independent of the platform specifics.
TABLE-US-00004 TABLE 3 Reference Phase Offset ID (deg) 0 phi_1 1
phi_2 2 . . . 3 4 5 6 7 8 9
[0064] The information is generated in the following sequence.
[0065] The first step is generation of the compensation table,
which is referred to a reference system as shown in Table 3. This
table is generated on a test system by the ATE (automated test
equipment). In some embodiments, this table may be stored in a
"trim-area", a protected memory in a non-volatile memory that is
persistent and will not be changed later on.
TABLE-US-00005 TABLE 4A Platform 1 H_1 Index of ID (A/m) phase trim
0 1 0 1 2 1 2 3 2 3 4 3 4 5 4 5 6 4 6 7 5 7 8 6 8 9 7 9 10 8
TABLE-US-00006 TABLE 4B Platform 2 H_2 Index of ID (A/m) phase trim
0 1 0 1 2 2 2 3 3 3 4 4 4 5 6 5 6 7 6 7 8 7 8 . . . 8 9 9 10
TABLE-US-00007 TABLE 5A Platform 1 RSSI_1 Index of ID (--) phase
trim 0 110 0 1 120 1 2 130 2 3 140 3 4 150 4 5 160 4 6 170 5 7 180
6 8 190 7 9 200 8
TABLE-US-00008 TABLE 5B Platform 2 RSSI_2 Index of ID (--) phase
trim 0 75 0 1 150 2 2 225 3 3 300 4 4 375 6 5 450 7 6 525 8 7 600 .
. . 8 675 9 750
[0066] In the second step, platform specific data can go into the
platform specific tables as shown in Table 4A or Table 4B, which
may be changed by customers or at least will be updated
specifically for customer's needs. In some embodiments, the
relevant data is stored in an "open" memory area. "Open" means it
is accessible for the customer.
[0067] In some embodiments, the table may be overwritten by the
customer, and it will be specific to a platform.
[0068] In some embodiments, the generation of the table (storing
the correct indices) may be done with help of spreadsheets.
[0069] Table 4A and 4B are basically equivalent to Table 5A and 5B.
The only difference is Table 4A and 4B refer to field-strength I-I,
while Table 5A and 513 refer to RSSI. In some embodiments, Table 4A
and 4B are the tables that contains the principal data. In some
embodiments, Table 5A and 5B are the important tables that are
applied, used, and stored. This can be due to RSSI being the
characteristic parameter being measured and used to determine the
phase offset.
[0070] In some embodiments, Table 4A and 4B can be known as
platform specific mapping tables (based on field strength H). In
some embodiments, Table 5A and 5B can be known as platform specific
mapping tables (based on RSSI). In some embodiments, the
information contained in Table 4A, 4B, 5A, and 5B can be presented
as platform specific mapping functions. For platform specific
mapping tables (which correspond to Phase Mapping
ph.sub.Platform(RSSI) 680 in FIG. 6), FIG. 6 shows the output to be
index 690. Index 690 is then used with Table 3 (which corresponds
to Phase Trim ph.sub.Ref(RSSI) 640 in FIG. 6) to obtain the
according "trimmed phase". Therefore, a platform specific mapping
tables is associated with an index. For a platform specific mapping
tables, the corresponding association would be more generally a
variable.
[0071] FIG. 6 shows a block diagram that provides an overview of
the method for calculating a phase that uses a reference phase trim
data to determine a phase offset, in accordance with some example
embodiments..FIG. 6 shows how the various values can be combined
for calculating a phase, in accordance with some example
embodiments.
[0072] Here is an embodiment of a procedure for applying the method
and system shown in FIG. 6.
[0073] In the first step, measure (or read) RSSI 630.
[0074] RSSI 630 is the dynamically measured metric that is
equivalent to the input voltage level. As the actual input voltage
value depends on platform parameters and RSSI trimming, the RSSI
does not give the absolute VRX voltage. Note that input voltage
level and in turn RSSI 630 is dependent on the field strength H
(610), the system scaling factor 620 is a correction of the
platform RSSI to the absolute VRX voltage.
[0075] In the second step, go into Table 5 (i.e., 5A or 5B,
depending on the platform) and get the index 690. In FIG. 6, Table
5 is represented by Phase Mapping ph.sub.Platform(RSSI) 680. In
some embodiments, Table 5 can be called a platform specific mapping
table or function.
[0076] In the third step, go into Table 3 with the index and get
the according "trimmed phase", which is the IC phase offset that
depends on the input voltage level (which is equivalent to RSSI).
In FIG. 6, Table 3 is represented by Phase Trim ph.sub.Ref(RSSI)
640. In some embodiments, Table 3 can be called a reference phase
trim data or a reference phase trim table.
[0077] In the fourth step, the "trimmed phase" will be applied to
the overall phase as per FIG. 6. In particular, the "trimmed phase"
will be combined with initial phase setting 650 and customer phase
offset 660 to contribute to a calibrated phase 670, which is
finally dialed into the system.
[0078] In this specification, example embodiments have been
presented in terms of a selected set of details. However, a person
of ordinary skill in the art would understand that many other
example embodiments may be practiced which include a different
selected set of these details. It is intended that the following
claims cover all possible example embodiments.
[0079] The various aspects, embodiments, implementations or
features of the described embodiments can be used separately or in
any combination. Various aspects of the described embodiments can
be implemented by software, hardware or a combination of hardware
and software.
[0080] The foregoing description, for purposes of explanation, used
specific nomenclature to provide a thorough understanding of the
described embodiments. However, it will be apparent to one skilled
in the art that the specific details are not required in order to
practice the described embodiments. Thus, the foregoing
descriptions of specific embodiments are presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the described embodiments to the precise
forms disclosed. It will be apparent to one of ordinary skill in
the art that many modifications and variations are possible in view
of the above teachings.
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