U.S. patent application number 10/249587 was filed with the patent office on 2004-10-28 for method of generating an alert for walkie-talkie when out of communicatable distance.
Invention is credited to Chen, Ming-Hui, Hsu, Jany-Yee.
Application Number | 20040214563 10/249587 |
Document ID | / |
Family ID | 33298098 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040214563 |
Kind Code |
A1 |
Hsu, Jany-Yee ; et
al. |
October 28, 2004 |
METHOD OF GENERATING AN ALERT FOR WALKIE-TALKIE WHEN OUT OF
COMMUNICATABLE DISTANCE
Abstract
A method of generating a warning signal for a walkie-talkie
includes: providing a detector and a timer; using the timer to
count time; using the detector to determine whether the strength of
a radio frequency (RF) signal which includes a standard CTCSS tone
received by the walkie-talkie is larger than a predetermined value;
using the detector to determine whether the strength of a RF signal
which includes a non-standard CTCSS tone received by the
walkie-talkie is larger than the predetermined value; if so,
resetting the timer; and issuing a warning signal when the time
counted by timer reaches a predetermined time.
Inventors: |
Hsu, Jany-Yee; (Yun-Lin
Hsien, TW) ; Chen, Ming-Hui; (Chang-Hua Hsien,
TW) |
Correspondence
Address: |
NAIPO (NORTH AMERICA INTERNATIONAL PATENT OFFICE)
P.O. BOX 506
MERRIFIELD
VA
22116
US
|
Family ID: |
33298098 |
Appl. No.: |
10/249587 |
Filed: |
April 22, 2003 |
Current U.S.
Class: |
455/421 |
Current CPC
Class: |
H04B 1/1027 20130101;
H04B 1/46 20130101 |
Class at
Publication: |
455/421 |
International
Class: |
H04Q 007/20 |
Claims
What is claimed is:
1. A method of generating a warning signal for a walkie-talkie
comprising: providing a detector and a timer in the walkie-talkie;
using the timer to count; when receiving a radio frequency (RF)
signal which consists of a standard continuous tone-coded squelch
system (CTCSS) tone, using the detector to determine whether a
strength of the radio frequency signal consisting of the standard
CTCSS tone is larger than a predetermined value; when receiving a
radio frequency (RF) signal which consists of a non-standard CTCSS
tone, using the detector to determine whether a strength of the
radio frequency signal consisting of the non-standard CTCSS tone is
larger than the predetermined value; resetting the timer when
either strength of the RF signal consisting of the non-standard
CTCSS tone or the RF signal consisting of the standard CTCSS tone
is larger than the predetermined value; and issuing a warning
signal when the time counted by timer reaches a predetermined
time.
2. The method of claim 1 wherein the predetermined value is larger
than a minimum receivable threshold.
3. A walkie-talkie for performing the method of claim 1.
4. A method of generating a radio frequency signal comprising:
providing a timer; using the timer to count; and when the time
counted by timer reaches a predetermined time, outputting the radio
frequency signal which consists of a non-standard CTCSS tone for a
certain time.
5. The method of claim 4 wherein the walkie-talkie comprises a
push-to-talk button, the method further comprising when pressing
the push-to-talk button, the walkie-talkie outputs a radio
frequency signal which includes a standard CTCSS tone.
6. The method of claim 4 wherein a frequency range of the
non-standard CTCSS tone is between 62.5 Hz-250 Hz but not
overlapping the frequency range used by the standard CTCSS
tone.
7. A walkie-talkie for performing the method of claim 4.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of generating an
alert for a walkie-talkie, more specifically, a method used in the
walkie-talkie for generating a warning signal when the
walkie-talkie will be out of communicable distance.
[0003] 2. Description of the Prior Art
[0004] A continuous tone-coded squelch system (CTCSS) has been
widely applied to wireless transmission, and is used to let a
plurality of users communicate with each other within a
predetermined communication area. The CTCSS adopts a low-frequency
CTCSS tone signal to distinguish signals transmitted via the same
physical channel. For instance, a prior art walkie-talkie utilizes
the CTCSS to achieve group communication. Please refer to FIG. 1,
which is a schematic diagram showing frequency bands used by the
prior art CTCSS. As shown in FIG. 1, a band ranging from 62.5 Hz to
250 Hz is used to transmit the above-mentioned low-frequency CTCSS
tone signal, and another band ranging from 300 Hz to 3.4 KHz is
used to transmit speech signals spoken by a user. The operation of
the CTCSS is described as follows. With regard to the prior art
walkie-talkie, 14 channels P.sub.1-P.sub.14 generally are adopted
to carry signals, and the 14 channels are physical channels. In
addition, 38 CTCSS tone signals T.sub.1-T.sub.38 individually
corresponding to different frequencies are used. One of the 38
CTCSS tone signals T.sub.1-T.sub.38 annexed to one physical channel
generates a specific logical channel, and the 14 physical channels
are capable of forming 532 (14*38) logical channels in total. When
a speaker sets the walkie-talkie with a physical channel P.sub.1
and a desired CTCSS tone signal T.sub.1, that is, the logical
channel set by the speaker becomes P.sub.1 (T.sub.1). After the
speaker presses a push-to-talk (PTT) button on the walkie-talkie,
the speaker is capable of outputting speech signals via the
walkie-talkie toward the predetermined communication area specified
by the walkie-talkie. If there are three listeners in the
predetermined communication area, and the three listener set their
own logical channels as P.sub.1 (T.sub.1), P.sub.1 (T.sub.38),
P.sub.2 (T.sub.1) respectively. For the first listener with a
logical channel P.sub.1 (T.sub.1) because his walkie-talkie
receives and transmits signals through the physical channel
P.sub.1, the walkie-talkie of the first listener will start
receiving speech signals spoken by the speaker. In addition, the
walkie-talkie of the first listener judges that the CTCSS tone
signal used by the speaker is T.sub.1. In other words, the speaker
and the first listener both adopt the same logical channel P.sub.1
(T.sub.1). Therefore, the walkie-talkie of the first listener then
outputs the received speech signals via an audio speaker. The first
listener is capable of hearing the speech signals spoken by the
speaker. For the second listener with a logical channel P.sub.1
(T.sub.38), because his walkie-talkie receives and transmits
signals through the physical channel P.sub.1, the walkie-talkie of
the second listener will start receiving speech signals spoken by
the speaker. However, the walkie-talkie of the second listener
judges that the CTCSS tone signal used by the speaker is not
T.sub.1, but T.sub.38. In other words, the speaker and the second
listener adopt different logical channels P.sub.1 (T.sub.1) and
P.sub.1 (T.sub.38). Therefore, the walkie-talkie of the second
listener then does not output the received speech signals via an
audio speaker. The second listener cannot hear the speech signals
spoken by the speaker. For the third listener with a logical
channel P.sub.2 (T.sub.1), because his walkie-talkie receives and
transmits signals through the physical channel P.sub.2, the
walkie-talkie of the third listener and that of the speaker use
different physical channels. With the unmatched physical channel,
the walkie-talkie of the third listener cannot acknowledge an
adequate signal strength indicated by a received signal strength
indicator (RSSI). Therefore, the walkie-talkie of the third
listener will not receive any speech signals spoken by the speaker.
That is, no speech signal is played by an audio speaker of the
walkie-talkie. The second and third listeners cannot hear any
speech signals spoken by the speaker, that is, the walkie-talkies
of the second and third listeners both detect the CTCSS tone signal
related to the received speech signals for actuating a signal
squelch function. To sum up, only the users using the same logical
channel can communicate with each other to achieve group
communication.
[0005] Please refer to FIG. 2, which is a block diagram of a prior
art walkie-talkie 10. The walkie-talkie 10 has an antenna 11, a
transceiver 12, a selector 14, a processor 16, a speaker 17, a
microphone 18, and a speech signal processor 20. The walkie-talkie
10 can receive and transmit radio frequency (RF) signals through
the antenna 11. With regard to receiving RF signals, the
transceiver 12 converts the high-frequency RF signal into a
low-frequency baseband signal Rx, and transmits the baseband signal
Rx to the selector 14. The selector 14 then outputs the baseband
signal Rx from an output port A. The processor 16 determines
frequency of a CTCSS tone signal according to the received baseband
signal Rx. Generally speaking, the processor 16 has a low-pass
filter (LPF) for extracting signals with frequencies ranging from
62.5 Hz to 250 Hz, and then the processor 16 judges the CTCSS tone
signal related to the baseband signal Rx to decide whether the
walkie-talkie 10 and the baseband signal Rx use the same logical
channel. If the walkie-talkie 10 and the baseband signal Rx use the
same logical channel, the processor 16 activates the speaker 17 to
proceed following signal output operation. That is, the speech
signal processor 20 has two analog filter circuits for extracting
signals with frequencies ranging from 300 Hz to 3.4 KHz, and the
extracted signals are played by the speaker 17. On the contrary, if
the walkie-talkie 10 and the baseband signal Rx use different
logical channels, the processor 16 does not actuate the speech
signal processor 20 and the speaker 17. The walkie-talkie 10,
therefore, does not output any speech signals transmitted by
unmatched logical channels. With regard to transmitting RF signals,
when the user presses the PTT button, the selector 14 will chose
the input port B, and the processor 16 simultaneously actuates the
microphone 18. Therefore, the speech signals spoken by the user are
inputted into the speech signal processor 20. As mentioned above,
the speech signal processor 20 uses filter circuits to extract
signals with frequencies ranging from 300 Hz to 3.4 KHz, and the
speech signal processor 20 outputs the extracted signals to the
CTCSS encoder 18. Based on a CTCSS code (CTCSS tone signal with a
specific frequency) set in the walkie-talkie 10, the processor 16
adds a corresponding CTCSS tone signal in the extracted signals
outputted from the speech signal processor 20 for forming a
baseband signal Tx. In the end, the transceiver 12 converts the
low-frequency baseband signal Tx into a high-frequency RF signal,
and the RF signal is then outputted via the antenna 11.
[0006] Generally speaking, because the radio signal easily is
obstructed by obstacles, such as trees, thick leaf and building, or
particle, such as steam and dust, which can limit the conversation
scope for the walkie-talkie. As for the user, although the common
walkie talkies are given a recommend conversation scope, but these
scopes are estimation values. Under different environments, in
fact, the really conversation scopes are not fixed, meaning that
the user cannot know the real conversation scopes with each other.
Therefore, unconsciously, a bad communication quality is caused by
terrain and environmental factor.
SUMMARY OF INVENTION
[0007] It is therefore a primary objective of the claimed invention
to provide a method used in a walkie-talkie for generating a
warning signal while leaving a conversation distance to solve the
aforementioned problem.
[0008] Briefly summarized, the claimed invention provides a method
for a walkie-talkie comprising providing a detector and a timer;
using the timer to count time;
[0009] using the detector to determine whether the strength of a
radio frequency (RF) signal which includes a standard CTCSS tone
received by the walkie-talkie is larger than a predetermined value;
using the detector to determine whether the strength of a RF signal
which includes a non-standard CTCSS tone received by the
walkie-talkie is larger than the predetermined value; if so,
resetting the timer; and issuing a warning signal when the time
counted by timer reaches a predetermined time.
[0010] These and other objectives of the claimed invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the invention, which
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a schematic diagram showing frequency bands used
by the prior art CTCSS.
[0012] FIG. 2 is a block diagram of a prior art walkie-talkie.
[0013] FIG. 3 is a schematic diagram of the walkie-talkies
according to the present invention.
[0014] FIG. 4 is a block diagram of the walkie-talkies according to
the present invention.
[0015] FIG. 5 is a timing diagram at transmission end depicted in
FIG. 4.
[0016] FIG. 6 is an operation flowchart with respect to the
walkie-talkie according to the present invention.
DETAILED DESCRIPTION
[0017] Please refer to FIGS. 3, 4, and 5. FIG. 3 is a schematic
diagram of the walkie-talkies 30, 40 according to the present
invention. FIG. 4 is a block diagram of the walkie-talkies 30, 40
according to the present invention. FIG. 5 is a timing diagram at
transmission end depicted in FIG. 4. The walkie-talkie 30 comprises
a push-to-talk (PTT) button 32, a microphone 34, a timer 35, a
processor 36, and a transmitter 38. The walkie-talkie 40 comprises
a receiver 42, a speaker 44, a detector 45, a processor 46, and a
timer 48. When pressing the PTT button 32 (time at t.sub.0-t.sub.1
and t.sub.2-t.sub.3 shown in FIG. 5), the processor 36 activates
the microphone 34 to receive a speech signal, which is converted
from human sound or ambient sound, and generates a standard CTCSS
tone signal according to a predetermined frequency. Finally, the
speech signal and the standard CTCSS tone signal both combining a
predetermined carrier is broadcasted. For example, as shown in FIG.
1, since 38 channels corresponding to the standard CTCSS tone
signals are distributed in the frequency range of 62.5 Hz-250 Hz,
if a user sets his walkie-talkie under a logical channel P.sub.1
(T.sub.38), i.e. using a physical channel P.sub.1 carrier, and a 38
standard CTCSS tone signal (given its frequency is 250 Hz), the
speech signal is broadcasted by using the logical channel P.sub.1
(T.sub.38). After releasing the PTT button 32, the timer 35 counts
until reaching a predetermined time T or until the PTT button 32 is
repressed again, and then the timer 32 is reset. The processor 36
outputs a non-standard CTCSS tone signal for a time A t whose
frequency range is between 62.5 Hz-250 Hz but not overlapping the
frequency range used by the standard CTCSS tone, when the time
counted by the timer 35 reaches a predetermined time T. Since the
standard CTCSS tone signal and the non-standard CTCSS tone signal
belong to the same frequency range, for preventing error, while the
standard CTCSS tone signal is being transmitted, the non-standard
CTCSS tone signal fails to be transmitted. For the following
explanation, assume that the non-standard CTCSS tone signal is
defined as 65 Hz and is not used by any standard CTCSS tone
signal.
[0018] The transmitter 42 of the walkie-talkie 40 is used for
receiving the RF signal from the walkie-talkie 30. In the preferred
embodiment, supposed that the transmitter 42 is set in advance for
receiving the carrier of the physical channel P.sub.1, the detector
45 is used for determining whether the RF signal received by the
transmitter 42 consists of the non-standard CTCSS tone signal. The
processor 46 is used for extracting the speech signal within the RF
signal. The speaker 44 is used to transform the speech signal into
sound waves and to output the sound waves. The timer 48 is used to
count time. In FIG. 5, the timer 48 starts to count when the
walkie-talkie 40 turns on at the time t.sub.0.
[0019] Please refer to FIG. 6 illustrating an operation flowchart
with respect to the walkie-talkie 40. The operation of the
walkie-talkie 40 is as follows:
[0020] Step 100: the timer 48 counts;
[0021] Step 102: the receiver 42 receives the RF signal;
[0022] Step 104: the detector 45 receives the RF signal;
[0023] Step 106: the detector 45 detects whether a standard CTCSS
tone signal is included within the RF signal; if it is, go to step
110, if not, go to step 108;
[0024] Step 108: the detector 45 detects whether a non-standard
CTCSS tone signal is included within the RF signal; if it is, go to
step 110, if not, go to step 102;
[0025] Step 110: the detector 45 detects whether either the
non-standard CTCSS tone signal strength or the standard CTCSS tone
signal strength is larger than a predetermined value; if it is, go
to step 112, if not, go to step 102;
[0026] Step 112: reset the timer 48.
[0027] After activating the walkie-talkie 40, the timer 48 counts
(step 100). The receiver 42 receives the RF signal with the carrier
using the physical channel P1 and eliminates that with the carrier
using the other physical channels. After receiving the RF signal,
the detector 45 will detect whether the standard CTCSS tone signal
with 250 Hz is included within the RF signal (step 106). If it is,
this represents the PTT button 32 of the walkie-talkie 30 is
pressed, and at this moment, the detector 45 will determine whether
the standard CTCSS tone signal strength is larger than a
predetermined value (step 110). If the standard CTCSS tone signal
with 250 Hz is not included within the RF signal, this means the
PTT button 32 is released, the detector 45 will detect whether the
non-standard CTCSS tone signal with 65 Hz is included within the RF
signal (step 108). When detecting the RF signal consisting of the
non-standard CTCSS tone signal with 65 Hz, the detector 45 will
compare the RF signal strength with a predetermined value (step
110). If the RF signal strength is larger than the predetermined
value, this means the user using the walkie-talkie 40 is still in a
receivable distance from another user using the walkie-talkie 30;
if not, this means the desired RF signal strength is close to the
threshold (i.e. RSSI depicted above), representing that the RF
signal from the walkie-talkie 30 is on the verge of being received
by the walkie-talkie 40. Notice that the predetermined value must
be larger than the threshold for the receivable signal strength,
so, if the signal strength is between the predetermined value and
the threshold, the user using the walkie-talkie 40 still listen to
voice from the walkie-talkie 30. If the timer 48 is not reset by
above-mentioned reason, when the time reaches a predetermined time
(2T for example), the walkie-talkie 40 will output a warning signal
so as to notify the user that a communicable distance between the
walkie-talkie 30 and the walkie-talkie 40 is close to the
threshold. At this time, the user should finish the conversation or
shorten the conversation distance, preventing sudden communication
termination or bad communication quality. After issuing the warning
signal, the timer 48 is reset, and the walkie-talkie 40 repeats
above procedures until being turned off.
[0028] In contrast to the prior art, the present invention
walkie-talkie sends a non-standard CTCSS tone signal regularly when
the walkie-talkie is in standby mode. In this way, no matter the
walkie-talkie is in standby mode or is operating, by detecting the
RF signal consisting of the non-standard CTCSS tone signal strength
in standby and detecting the RF signal consisting of the standard
CTCSS tone signal strength while operating, the walkie-talkie is
capable of timely alarming the user to take care of conversation
distance, regardless of location wherever the user is. When
receiving a warning signal, the user has sufficient time to finish
the conversation or to shorten the conversation distance,
preventing sudden communication termination or bad communication
quality.
[0029] Those skilled in the art will readily observe that numerous
modifications and alterations of the method may be made while
retaining the teachings of the invention. Accordingly, the above
disclosure should be construed as limited only by the metes and
bounds of the appended claims.
* * * * *