Title: Echo plug for a wireless telephone
Abstract: Echo plugs are plugged into the hands-free jacks of wireless telephones to facilitate testing. One echo plug has a pin and a circuit. The pin is physically compatible with the hands-free jack of a wireless telephone. The pin has a speaker connection and a microphone connection. The circuit couples the speaker connection to the microphone connection. In operation, this echo plug receives a signal from the speaker connection of the hands-free jack and transfers the signal to the microphone connection of the hands-free jack. Another echo plug has two pins and a circuit. The pins are physically compatible with the hands-free jack of a wireless telephone. The first pin has a speaker connection, and the second pin has a microphone connection. The circuit couples the speaker connection of the first pin to the microphone connection of the second pin. In operation, this echo plug receives a signal from the speaker connection of a hands-free jack in a first wireless telephone and transfers the signal to the microphone connection of a hands-free jack in a second wireless telephone.
Patent Number: 6,909,894 Issued on 06/21/2005 to Kingsley, et al.
| Inventors:
|
Kingsley; Paul Michael (Monument, CO);
Doerr; Bradley Scott (Colorado Springs, CO)
|
| Assignee:
|
Agilent Technologies, Inc. (Palo Alto, CA)
|
| Appl. No.:
|
550863 |
| Filed:
|
April 17, 2000 |
| Current U.S. Class: |
455/423; 379/21; 379/29.01; 455/424; 455/425 |
| Intern'l Class: |
H04Q 007/20 |
| Field of Search: |
455/423,424,425,426
379/101-35,21,220.1,270.1,270.6,270.7,290.1
|
References Cited [Referenced By]
U.S. Patent Documents
| 4602134 | Jul., 1986 | Atkinson et al.
| |
| 4903323 | Feb., 1990 | Hendershot.
| |
| 5347566 | Sep., 1994 | Law et al.
| |
| 5687213 | Nov., 1997 | Larkin.
| |
| 5696813 | Dec., 1997 | Sears et al.
| |
| 5768689 | Jun., 1998 | Borg.
| |
| 5784406 | Jul., 1998 | DeJaco et al.
| |
| 5790657 | Aug., 1998 | Fujiwara.
| |
| 5875398 | Feb., 1999 | Snapp.
| |
| 5943617 | Aug., 1999 | Nakamura.
| |
| 6081724 | Jun., 2000 | Wilson.
| |
| 6108404 | Aug., 2000 | Hardy et al.
| |
Primary Examiner: Trost; William
Assistant Examiner: D'Agosta; Stephen
Claims
1. An echo plug apparatus for use with a wireless telephone having a hands-free
jack, the echo plug apparatus comprising:
a pin that is physically compatible with the hands-free jack of the wireless
telephone and that is configured with a speaker connection and a microphone connection;
and
a circuit configured to couple the speaker connection to the microphone connection.
2. The echo plug apparatus of claim 1 wherein the circuit is configured to attenuate signals.
3. The echo plug apparatus of claim 1 wherein the circuit is configured to delay signals.
4. The echo plug apparatus of claim 1 wherein the circuit is configured to cancel
side-tones from signals.
5. An echo plug apparatus for use with a first wireless telephone having a first
hands-free jack and a second wireless telephone having a second hands-free jack,
the echo plug apparatus comprising:
a first pin that is physically compatible with the first hands-free jack of the
first wireless telephone and that is configured with a speaker connection;
a second pin that is physically compatible with the second hands-free jack of
the second wireless telephone and that is configured with a microphone connection;
and
a circuit configured to couple the speaker connection to the microphone connection.
6. The echo plug apparatus of claim 5 wherein the circuit is configured to attenuate signals.
7. The echo plug apparatus of claim 5 wherein the circuit includes a cable coupled
between the first pin and the second pin.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention is related to the field of wireless communications, and in particular,
to an echo plug that plugs into the hands-free jack of a wireless telephone to
facilitate testing.
BACKGROUND OF THE INVENTION
The demand for wireless communication services is growing dramatically, and there
is corresponding growth in the need to test wireless telephones and communication
systems. A common testing technique uses a test system that is equipped with a
transmit telephone circuit and a receive telephone circuit. The transmit telephone
circuit places a test call to the receive telephone circuit over a wireless telephone.
The transmit telephone circuit then transmits test signals over the call connection
to the receive telephone circuitry. The test system compares the received test
signals to the transmitted test signals to generate statistics regarding voice
quality and round-trip delay. One example of a test system is the Voice Quality
Tester supplied by Agilent Technologies. Two common voice quality measurements
are Perceptual Speech Quality Measure (PSQM) and Perceptual Analysis Measurement
System (PAMS).
The above-described test call is placed as follows. The transmit telephone circuit
is connected to a wireless telephone using a special connector that is customized
for the wireless telephone. The receive telephone circuit is connected to a telephone
jack that is coupled to the communication network. The wireless telephone places
a test call using a test telephone number. A wireless transceiver in the communication
system handles the test call from the wireless telephone, and the communication
system routes the call to the telephone jack. The receive telephone circuit that
is connected to the telephone jack answers the call. The test system is now connected
to a communications loop through the communication network and is ready to conduct
voice quality and delay tests.
Wireless telephone suppliers and service providers need to test their equipment
under various conditions to ensure quality. Unfortunately, the above-described
testing technique inhibits robust testing under dynamic test conditions. For example,
the test system is coupled to the wireless telephone with a special connector that
is not compatible with other types of wireless telephones. Many wireless telephones
do not have their own special connectors, and even if they did, the use of many
different special connectors is cumbersome. As a result, the test system cannot
effectively test many different types of wireless telephones. In addition to this
restriction, mobility testing is cumbersome because the test system must be moved
along with the wireless telephone.
The public telephone network internally performs similar tests. On a percentage
of calls, the originating telephone switch requests a continuity test in the call
set-up signaling message. In response to the request, the terminating telephone
switch cross-connects the connections for the call. The originating telephone switch
then transmits a tone to the terminating telephone switch where the tone is looped
back to the originating telephone switch. The continuity test is successful if
the originating telephone switch receives the tone. Continuity testing is inadequate
to test wireless telephones and communication systems.
SUMMARY OF THE INVENTION
The invention solves the above problems with an echo plug that facilitates robust
testing under dynamic test conditions by looping test signals through a wireless
telephone back to a test system. The echo plug fits into the hands-free jack of
a wireless telephone and is easily moved from one wireless telephone to another.
The wireless telephones retain their mobility with the echo plug attached. The
echo plug facilitates the testing of different wireless telephones at various locations
over different communication systems.
One echo plug has a pin and a circuit. The pin is physically compatible with
the hands-free jack of a wireless telephone. The pin has a speaker connection and
a microphone connection. The circuit couples the speaker connection to the microphone
connection. In operation, this echo plug receives a signal from the speaker connection
of the hands-free jack and transfers the signal to the microphone connection of
the hands-free jack.
Another echo plug has two pins and a circuit. The pins are physically compatible
with the hands-free jack of a wireless telephone. The first pin has a speaker connection,
and the second pin has a microphone connection. The circuit couples the speaker
connection of the first pin to the microphone connection of the second pin. In
operation, this echo plug receives a signal from the speaker connection of a hands-free
jack in a first wireless telephone and transfers the signal to the microphone connection
of a hands-free jack in a second wireless telephone.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram that illustrates system configuration in an example
of the invention.
FIG. 2 is a schematic diagram that illustrates an echo plug in an example of
the invention.
FIG. 3 is a schematic diagram that illustrates an echo plug with signal processing
in an example of the invention.
FIG. 4 is a schematic diagram that illustrates signal processing components
in an example of the invention.
FIG. 5 is a block diagram that illustrates system operation in an example of
the invention.
FIG. 6 is a block diagram that illustrates system configuration in an example
of the invention.
FIG. 7 is a schematic diagram that illustrates an echo plug in an example of
the invention.
FIG. 8 is a schematic diagram that illustrates an echo plug with attenuation
in an example of the invention.
FIG. 9 is a block diagram that illustrates system operation in an example of
the invention.
FIG. 10 is a flow diagram that illustrates a testing method in an example of
the invention.
FIG. 11 is a flow diagram that illustrates a testing method in an example of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
System Configuration-FIG. 1
FIG. 1 is a block diagram that illustrates system configuration in an example
of the invention. The system includes communication system
100, wireless
telephone
110, and test system
120. Communication system
100
comprises jack
101 coupled to wireless transceiver
102 by communications
path
103. Communications path
103 could include multiple communication
devices that are omitted for clarity. Wireless telephone
110 comprises hands-free
jack
111 and communicates with wireless transceiver
102 over wireless
link
112. Hands-free jack
111 is configured with speaker and microphone
connections that allow the connection of headsets and other audio devices to wireless
telephone
110. The speaker connection is sometimes referred to as "audio
out", and the microphone connection is sometimes referred to as "audio in". Test
system
120 is connected to jack
101 by telephone cable
121.
The above components could be conventional.
The system also includes echo plug
130 that is plugged into hands-free
jack
111. Echo plug
130 has a pin and pin handle that can be the
similar to those of conventional hands-free plugs. Echo plug
130 is physically
compatible with hands-free jack
111 of wireless telephone
110. Echo
plug
130 is configured with a speaker connection and a microphone connection
that couple to their respective connections of hands-free jack
111. Echo
plug
130 also has a circuit that is configured to couple the speaker connection
to the microphone connection. Thus, echo plug
130 loops the "audio out"
of wireless telephone
110 back to the "audio in". Advantageously, echo plug
130 facilitates testing by looping test signals back to test system
120.
Echo Plug Configurations FIGS. 2-4
FIGS. 2-4 depict specific examples of echo plugs in accord with the present
invention. Those skilled in the art will appreciate variations from these example
that do not depart from the scope of the invention. Those skilled in the art will
also appreciate that various features described below could be combined to form
multiple variations of the invention.
FIG. 2 is a schematic diagram that illustrates an echo plug in an example of
the invention. Echo plug
230 comprises pin
231 and circuit
232.
Pin
231 is physically compatible with a 2.5 mm hands-free jack of a wireless
telephone, although other sizes are used in other examples of the invention. Pin
231 has speaker connection
233, microphone connection
234,
and ground connection
235. Circuit
232 couples speaker connection
233 to microphone connection
234. When echo plug
230 is plugged
into the hands-free jack of a wireless telephone, signals that are sent to speaker
connection
233 are looped back to microphone connection
234.
FIG. 3 is a schematic diagram that illustrates an echo plug with signal processing
components in an example of the invention. Echo plug
330 comprises pin
331
and circuit
332. Pin
331 is physically compatible with a 2.5 mm hands-free
jack of a wireless telephone, although other sizes are used in other examples of
the invention. Pin
331 has speaker connection
333, microphone connection
334, and ground connection
335. Circuit
332 couples speaker
connection
333 to microphone connection
334 and includes signal processing
components
336. When echo plug
330 is plugged into the hands-free
jack of a wireless telephone, signals that are sent to speaker connection
333
are transferred through signal processing components
336 and looped back
to microphone connection
334.
FIG. 4 is a schematic diagram that illustrates signal processing components
336 in an example of the invention. Signal processing components
336
comprise side-tone cancellation circuit
441, delay circuit
442, and
attenuation circuit
443 coupled in series within circuit
332. The
order of circuits
441-
443 within circuit
332 can vary.
In the typical telephone, side-tones are voice signals from the microphone that
are fed back to the speaker so the caller can hear what they are saying. Side-tone
cancellation circuitry is commonly employed in speaker phones to eliminate side
tones. Side-tone cancellation circuit
441 cancels side-tones in a similar
fashion to avoid a potential feedback loop created by circuit
332 and side-tone
connections in the wireless telephone.
In telephone networks, the voice signal echoes off of wiring equipment at the
listener's site back to the speaker's site. The speaker hears this echo of their
own voice if the distances between the callers is great enough. To remove the annoying
echo, echo cancellers in the communication system subtract a copy of the signal
that is transmitted in one direction from the signal that is transmitted in the
other direction. The subtraction is timed to coincide with the time the annoying
echo reaches the echo canceller. Echo cancellers adversely impact testing using
echo plug
330 because they attempt to cancel the test signal intentionally
looped back by circuit
332. Delay circuit
442 delays the test signal
on circuit
332 past the time when echo cancellers remove echo. Thus, the
echo cancellers remove ambient echo before the test signal from echo plug
330
reaches the echo canceller.
Some wireless telephones amplify the signals that are transferred to the speaker
and that are received from the microphone. A test signal passing through echo plug
330 may be too powerful a signal for the microphone input. Attenuation circuit
443 reduces the strength of signals passing through echo plug
330
to offset any input level mismatch. One example of attenuation circuit
443
is a resister coupled between speaker connection
333 and microphone connection
334, and a capacitor coupled between microphone connection
334 and
ground connection
335.
System Operation-FIG. 5
FIG. 5 is a block diagram that illustrates system operation in an example of
the invention. The system is the same as depicted on FIG.
1 and includes
communication system
100, wireless telephone
110, test system
120,
and echo plug
130. Echo plug
130 is plugged into hands-free jack
111 of wireless telephone
110. A test call is generated between test
system
120 and wireless telephone
110 through communication system
100. After the test call is answered, test system
120 transfers a
test signal to the wireless telephone
110 over call paths
541,
542,
and
543. Wireless telephone
110 transfers the test signal to the
speaker connection of its hands-free jack
111. Echo plug
130 provides
call path
544 to return the test signal to the microphone connection of
hands-free jack
111. Echo plug
130 may apply side-tone cancellation,
delay, and attenuation to the test signal on call path
544. The microphone
connection of hands-free jack
111 transfers the test signal to the transmit
circuitry of wireless telephone
110. Wireless telephone
110 transfers
the test signal to test system
120 over call paths
545,
546,
and
547. Test system
120 compares the received test signal to the
transmitted test signal to generate statistics regarding voice quality and round-trip delay.
Alternate System Configuration-FIG. 6
FIG. 6 is a block diagram that illustrates an alternate system configuration
in an example of the invention. The system includes communication system
600,
wireless telephone
610, wireless telephone
615, and test system
620.
Communication system
600 comprises jacks
601 and
604 respectively
coupled to wireless transceiver
602 by communications path
603 and
605. Communications paths
603 and
605 could include multiple
communication devices that are omitted for clarity. Wireless telephones
610
and
615 respectively comprise hands-free jacks
611 and
616.
Wireless telephones
610 and
615 respectively communicate with wireless
transceiver
602 over wireless links
612 and
617, although
they could communicate with separate transceivers in other examples of the invention.
Hands-free jacks
611 and
616 are each configured with speaker and
microphone connections. Test system
620 is respectively connected to jacks
601 and
604 by telephone cables
621 and
622. The above
components could be conventional.
The system also includes echo plug
630 that comprises plugs
630A
and
630B that are connected by cable
630C. Plug
630A is plugged
into hands-free jack
611, and plug
630B is plugged into hands-free
jack
616. Plugs
630A and
630B each have a pin and pin handle
that can be the similar to those of conventional hands-free plugs. Plugs
630A
and
630B are physically compatible with hands-free jacks
611 and
616. Plugs
630A and
630B are each configured with a speaker
connection and a microphone connection that couple to their respective connections
of hands-free jacks
611 and
616. Echo plug
630 has a circuit
passing through cable
630C that is configured to couple the speaker connection
of plug
630A to the microphone connection of plug
630B. Thus, echo
plug
630 loops the "audio out" of wireless telephone
610 to the "audio
in" of wireless telephone
615. Advantageously, echo plug
630 facilitates
testing by looping test signals back to test system
620.
The use of separate wireless telephones
610 and
615 effectively
eliminates the side-tone and echo cancellation problems described with respect
to FIG.
4. There is no potential for an undesirable feedback loop between
the echo plug
630 and side-tone circuitry in wireless telephones
610
or
615. There is no echo cancellation between the separate connections from
test system
620 to wireless telephones
610 and
615.
Alternate Echo Plug Configurations FIGS. 7-8
FIGS. 7-8 depict specific examples of echo plugs in accord with the present
invention. Those skilled in the art will appreciate variations from these example
that do not depart from the scope of the invention. Those skilled in the art will
also appreciate that various features described below could be combined to form
multiple variations of the invention.
FIG. 7 is a schematic diagram that illustrates an echo plug in an example of
the invention. Echo plug
730 comprises plug
730A coupled to plug
730B by cable
730C. Plugs
730A and
730B have respective
pins
731A and
731B that are physically compatible with a 2.5 mm hands-free
jack of a wireless telephone, although other sizes are used in other examples of
the invention. Pin
731A has a speaker connection
733A, microphone
connection
734A, and ground connection
735A. Pin
731B has
a speaker connection
733B, microphone connection
734B, and ground
connection
735B. Circuit
732 passes through cable
730C to
couple speaker connection
733A to microphone connection
734B. When
echo plug
730 is plugged into the hands-free jacks of two wireless telephones,
signals that are sent to speaker connection
733A are looped back to microphone
connection
734B.
FIG. 8 is a schematic diagram that illustrates an echo plug with attenuation
in an example of the invention. Echo plug
830 comprises plug
830A
coupled to plug
830B by cable
830C. Plugs
830A and
830B
have respective pins
831A and
831B that are physically compatible
with a 2.5 mm hands-free jack of a wireless telephone, although other sizes are
used in other examples of the invention. Pin
831A has a speaker connection
833A, microphone connection
834A, and ground connection
835A.
Pin
831B has a speaker connection
833B, microphone connection
834B,
and ground connection
835B. Circuit
832 passes through cable
830C
to couple speaker connection
833A to microphone connection
834B through
attenuation circuit
843. When echo plug
830 is plugged into the hands-free
jacks of two wireless telephones, signals that are sent to speaker connection
833A
are passed through attenuation circuit
843 and looped back to microphone
connection
834B.
Some wireless telephones amplify the signals that are transferred to the speaker
and that are received from the microphone. A test signal passing through echo plug
830 may be too powerful a signal for the microphone input. Attenuation circuit
843 reduces the strength of signals passing through echo plug
830
to offset any input level mismatch. One example of attenuation circuit
843
is a resister coupled between circuit
832 from speaker connection
833A
and microphone connection
834B, and a capacitor coupled between microphone
connection
834B and ground connection
835B.
Alternate System Operation-FIG. 9
FIG. 9 is a block diagram that illustrates system operation in an example of
the invention. The system is the same as depicted on FIG.
6 and includes
communication system
600, wireless telephones
610 and
615,
test system
620, and echo plug
630. Echo plug
630 is plugged
into hands-free jacks
611 and
616 of respective wireless telephones
610 and
615. A first test call is generated through communication
system
600 between test system
620 and wireless telephone
610.
A second test call is generated through communication system
600 between
test system
620 and wireless telephone
615. After the test calls
are answered, test system
620 transfers a test signal to the wireless telephone
610 over call paths
941,
942, and
943. Wireless telephone
610 transfers the test signal to the speaker connection of hands-free jack
611. Echo plug
630 provides call path
944 to return the test
signal to the microphone connection of hands-free jack
616. Echo plug
630
may apply attenuation to the test signal on call path
944. The microphone
connection of hands-free jack
616 transfers the test signal to the transmit
circuitry of wireless telephone
615. Wireless telephone
615 transfers
the test signal to test system
620 over call paths
945,
946,
and
947. Test system
620 compares the received test signal to the
transmitted test signal to generate statistics regarding voice quality and round-trip delay.
Testing Methods-FIGS. 10-11
FIG. 10 is a flow diagram that illustrates a testing method in an example of
the invention for systems like that of FIG.
1. The method starts by plugging
the echo plug into the hands-free jack of a wireless telephone. A test call is
then generated between the test system and the wireless telephone. The test system
transmits a test signal to the wireless telephone over the test call. The echo
plug loops the test signal from the speaker connection of the hands-free jack to
the microphone connection of the hands-free jack. The wireless telephone transmits
the test signal from the microphone connection of the hands-free jack to the test
system over the test call. If mobility testing is desired at this time, then the
wireless telephone is moved during test signal transmission. The test system generates
test results in response to the first test signal. If there is another wireless
telephone to test, then the echo plug is unplugged and plugged into the hands-free
jack of the other wireless telephone. The above test sequence is repeated for the
other wireless telephone. If mobility testing is desired at this time, then the
wireless telephones are moved to a new test location, and the test sequence is repeated.
FIG. 11 is a flow diagram that illustrates an alternative testing method in
an example of the invention for systems like that of FIG.
6. The method
starts by plugging the echo plug into the hands-free jacks of two wireless telephones.
Two test calls are then generated between the test system and the two wireless
telephones. The test system transmits a test signal to the first wireless telephone
over the first test call. The echo plug loops the test signal from the speaker
connection of the hands-free jack in the first wireless telephone to the microphone
connection of the hands-free jack in the second wireless telephone. The second
wireless telephone transmits the test signal from the microphone connection of
the hands-free jack to the test system over the second test call. If mobility testing
is desired at this time, then the wireless telephones are moved during test signal
transmission. The test system generates test results in response to the first test
signal. If there are other wireless telephones to test, then the echo plug is unplugged
and plugged into the hands-free jacks of the two other wireless telephones. The
above test sequence is repeated for the two other wireless telephones. If mobility
testing is desired at this time, then the wireless telephones are moved to a new
test location, and the test sequence is repeated.
The modularity of the echo plug provides for convenient testing of many different
wireless telephones. After a wireless telephone is tested, the echo plug is easily
moved to another wireless telephone for another test. This procedure can be repeated
for many different wireless telephones because many wireless telephones have hands-free jacks.
Different communication systems can be tested by using two wireless telephones
that are subscribed to the different communication systems. The test system places
a first test call to the first wireless telephone over the first communication
system and generates test results. The echo plug is then moved from the first wireless
telephone to the second wireless telephone. The test system then places a second
test call to the second wireless telephone over the second communication system
and generates test results.
The mobility of the wireless telephone and echo plug provides convenient mobility
testing. The wireless telephone and echo plug can be easily moved during or after
the test. Mobility testing can be combined with the above testing techniques to
test many different wireless telephones at many different locations over various
communication systems.
Those skilled in the art will appreciate variations of the above-described
embodiments that fall within the scope of the invention. As a result, the invention
is not limited to the specific examples and illustrations discussed above, but
only by the following claims and their equivalents.
*
