Pulse or digital communications – Transceivers
Reexamination Certificate
1999-02-09
2002-08-06
Chin, Stephen (Department: 2734)
Pulse or digital communications
Transceivers
C375S130000, C375S296000, C375S346000, C455S566000
Reexamination Certificate
active
06430217
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a digital wireless transceiver apparatus, in particular, to a portable telephone device.
2. Description of the Related Art
FIG. 1
illustrates an external view of a conventional portable telephone device. The portable telephone device comprises a telephone unit
10
and a headset
20
. The headset
20
may be optionally coupled to the unit
10
. The unit
10
includes a telephone housing
11
and an antenna
12
that can be pulled out from the housing
11
. A built-in earphone
13
, a built-in microphone
14
, operation keys
15
, a display
16
, and a transceiver section
17
that is hidden by the housing
11
are installed in the telephone unit
10
. The housing
11
has a jack
18
for coupling the headset
20
.
The headset
20
comprises a plug
21
for coupling with the jack
18
, a headphone
22
corresponding to the earphone
13
, a headset microphone
23
corresponding to the built-in microphone
14
and a paired cable
24
for connecting the headphone
22
and the headset microphone
23
to the unit
10
.
Generally, portable telephones of this kind are designed for being used with an earphone
13
and a built-in microphone
14
, being held in a hand, without using a headset
20
. However, the telephones are designed for being used optionally with the headset
20
so as to avoid such a danger that the driver of a motor vehicle holds a telephone unit
10
while driving the vehicle.
When the headset
20
is to be used, the plug
21
should be inserted into the jack
18
of the telephone unit
10
. The insertion causes the earphone
13
and the built-in microphone
14
to be disconnected from the transceiver section
17
while the headphone
22
and the headset microphone
23
are connected to the transceiver section
17
, thereby enabling a use of the telephone unit
10
without holding it in a hand.
When, however, the headphone
22
is used for a digital portable telephone, a problem has been accounted, as follows. The conventional analog portable telephone transmits a radio wave with a constant amplitude during a telephone call. On the other hand, a digital portable telephone is adapted to sample an analog voice signal generated during a call is sampled with a fixed period of time for converting it into a digital signal. The thus resulted digital signal is temporarily stored in a buffer memory. The stored digital signal is spread with spread codes in a spread spectrum scheme and converted into a fast digital radio signal of, for example, 800 MHz for transmission through the antenna
12
. In this instance, it is to be noted that the radio signal may be intermittently transmitted as a burst-mode signal under some conditions, for example, in the case of presence or absence of a voice signal to be transmitted or in the case of the line congestion.
When the headset
20
is connected the digital portable telephone, the radio wave of 800 MHz intermittently transmitted through the antenna
12
of the telephone unit
10
is caught by the cable
24
of the headset
20
. The caught radio wave is interrupted with a low frequency component of, for example, several hundred Hz. to particular low frequency depends on a period of on/off control for the transmission of the radio wave. The burst signal may enter a voice amplifier in a receiver channel of the transceiver unit
17
, or may be detected by the headphone
22
, thereby causing noises with a frequency of several hundreds Hz in the headphone
22
. Owing to the noise output from the headphone
22
, the clarity of a caller voice will be significantly degraded. As such, there arises such a problem that the effective use of the headphone
22
is impaired.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a digital wireless transceiver such as a digital portable telephone device which is free from noises occurring in a headset that is connected thereto.
The foregoing and other problems are overcome and the object of the invention is realized by apparatus in accordance with the invention.
The present invention provides in a first aspect, a digital wireless transceiver apparatus having transmitting means for converting a voice signal into a digital signal to store the converted signal and f or modulating a carrier wave with spread spectrum codes of the stored signal, the transmitting means being operable f or transmitting the modulated signal in an intermittent mode; receiving means for receiving a spread radio signal for demodulating the received signal to obtain a voice signal; acoustic means for converting the voice signal into an acoustic sound; and transfer means for transferring the voice signal to the acoustic means through a cable; wherein the transfer means comprising: a first high-frequency eliminating means for preventing a high-frequency signal induced in the transfer means by the transmitted signal from arriving at the acoustic means.
Further, a digital wireless transceiver apparatus in a second aspect of the present invention is characterized by the transfer means further includes a second high-frequency eliminating means for preventing the high-frequency signal from arriving at the receiving means.
Still further, a digital wireless transceiver apparatus according to claim 2, wherein the transfer means includes a detachable coupler for relaying the voice signal between the receiving means and a paired cable interconnecting the coupler and the acoustic means, wherein the second high-frequency eliminating means being provided between the coupler and the paired cable.
REFERENCES:
patent: 5191602 (1993-03-01), Regan et al.
patent: 5200720 (1993-04-01), Yi
patent: 5557653 (1996-09-01), Paterson et al.
Nakagiri Hiroshi
Suzuki Katsuya
Chin Stephen
Fan Chieh M.
Oki Electric Industry Co, Ltd.
Rabin & Berdo P.C.
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