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Mobile Phone Patent Abstract
The invention relates to a mobile phone (1) and specifically to
an interface for connecting external signals received from and transmitted
to external devices to the mobile phone, and to an interface configuration
for connecting the mobile phone to external signals. In the mobile
phone of the invention, external digital signals are basically received
and transmitted over a coaxial line (6) connected to an RF signal
connector (3). In the interface configuration of the invention an
interface unit (31) is provided at one end of the coaxial line (6),
the interface unit controlling the transmission of external signals
connected to connectors (35, 60, 61a, 61b, 61c) over the coaxial
line (6) between the mobile phone (1) and the external devices.
In one embodiment of the invention power supply to the mobile phone
also takes place over the RF connector (3) and the coaxial line
(6) connected to this.
Mobile Phone Patent Claims
We claim:
1. A mobile phone comprising:
an RF signal interface containing a connector (3), over which input
and output RF signals pass on a single coaxial conductor (6) connected
to the connector (3), and
one or more interfaces for at least some of digital input and output
signals, comprising audio signals, control signals and data signals,
characterised in that digital signal interfaces are connected to
the RF signal interface such that the digital input and output signals
are received and transmitted through the connector (3) also over
said same coaxial conductor (6) over which said input and output
RF signals pass,
further characterised in that the digital input and output signals,
when transferred on the coaxial conductor (6), are modulated onto
a second carrier wave that is separate from first carrier waves
that comprise said input and output RF signals.
2. A mobile phone as claimed in claim 1, characterised in that
the frequency of the second carrier wave is within the range of
1 to 5 MHz.
3. A mobile phone as claimed in claim 1, characterised in that
the digital input and output signals are transferred on the coaxial
conductor (6) in a message form.
4. A mobile phone as claimed in claim 1, and further comprising:
means (21, 22, 23, 24, 25) for separating RF signals from digital
signals passing to the connector (3) on the coaxial conductor and
means (13) for receiving and separating digital signals and for
transmitting digital signals.
5. A mobile phone as claimed in claim 4, characterised in that
the means for separating RF signals from the digital signals comprise
a quarter-wave transmission line (21) and a capacitor (25) to prevent
RF signals from reaching the line (10) for digital signals.
6. A mobile phone as claimed in claim 4, characterised in that
the means (13) for receiving and separating digital signals and
for transmitting digital signals include:
control means (71) for controlling transmission and reception,
modulating means (73) for modulating digital signals to be transmitted
onto the second carrier wave,
demodulating means (74) for demodulating received digital signals,
buffer means (72, 75), respectively, for digital signals to be
transmitted and for digital signals to be received, and
means (76) for sensing the state of the interface for the purpose
of controlling transmission and reception.
7. A mobile phone as claimed in claim 1, and further comprising
a DC interface for providing a direct current supply to the mobile
phone, characterised in that the DC interface is also connected
to the RF signal interface such that direct current is supplied
through the connector (3) included in the RF signal interface and
the coaxial conductor (6) connected to the connector.
8. A mobile phone as claimed in claim 7, and further comprising
means (26, 27) for separating supplied direct current from RF signals
and digital signals.
9. An interface configuration for connecting a mobile phone to
external output and input signals, comprising external RF signals
and external audio signals, control signals and data signals, characterised
in that an interface unit (31) is connected to an end of a single
coaxial conductor (6) opposite to the mobile phone, the interface
unit comprising:
means (51, 52, 53, 54, 55) for separating RF signals and digital
signals both of which are received on the same coaxial conductor
(6),
means (43) for receiving and separating digital signals coming
from the coaxial conductor (6) and for transmitting digital signals
to the coaxial conductor,
a physical interface (35) for RF signals,
physical interfaces (61) for external input and output signals,
comprising output and input audio signals, control signals and data
signals corresponding to the digital signals, and
means (42) for processing and controlling external input signals
passing between the physical interfaces (61), and the means (43)
for transmitting and receiving digital signals, into corresponding
digital input signals, and for processing digital output signals
into corresponding external output signals,
wherein the digital input and output signals, when transferred
on the coaxial conductor (6), are modulated onto a second carrier
wave that is separate from first carrier waves that comprise said
RF signals.
10. An interface configuration as claimed in claim 9, characterised
in that the interface unit (31) further comprises:
a physical interface (60) for receiving supply current for current
fed into the mobile phone,
means (58, 41) for processing received supply current into direct
current to be supplied to the mobile phone and
means (56, 57) for filtering direct current supplied to the mobile
phone and for also feeding the filtered direct current into the
same coaxial conductor (6) that conveys the RF signals and the digital
signals.
11. A mobile phone, comprising:
an external RF signal interface through which input and output
RF signals pass over an external RF conductor, the RF signals having
frequencies within a transmission and reception band of the mobile
phone; and
an external digital interface for inputting and outputting digital
signals, said digital signals being input and output over said same
external RF conductor as said RF signals, and being modulated onto
a carrier having a frequency that differs from frequencies within
said transmission and reception band, said digital signals being
modulated onto said carrier for the purpose of transmission through
said RF conductor.
12. A mobile phone as in claim 11, and further comprising a power
interface for coupling DC operating power into said mobile phone,
the DC operating power being input to said mobile phone over said
same external RF conductor as said RF signals and said digital signals.
13. A mobile phone as in claim 11, wherein said external RF conductor
is comprised of a coaxial cable.
Mobile Phone Patent Description
FIELD OF THE INVENTION
The invention relates to a mobile phone, and specifically to an
interface for connecting external signals, received from and transmitted
to external devices, to the mobile phone, and to an interface arrangement
for connecting the mobile phone to external signals. The mobile
phone interface and interface configuration of the invention are
practicable in any digitally operated mobile phones.
BACKGROUND OF THE INVENTION
As a rule, mobile phones comprise a plurality of interfaces including
connectors for external signals and devices. The phone is usually
provided with an interface for RF signals received and transmitted
over an external aerial, and with a connector usually coaxial for
this purpose, to which a coaxial line from an external aerial is
connected. Control or data signals received or transmitted by the
phone are transferred via a separate connector. Input and output
audio signals frequently have a specific interface and connector.
Charging current is supplied to the phone as D.C. supply over a
specific connector. FIG. 1 is a schematic view of a typical, well-equipped
hand-held mobile phone 1, which, besides its own aerial 1, comprises
a coaxial RF connector 3 for input and output RF signals transmitted
over an external aerial, a DC connector 4 for power supply and a
12-pin basic connector 5 for external audio, control and data signals.
The invention relates to a digitally operated mobile phone, comprising
at least one interface including a connector for RF signals and
requiring additional interfaces for at least some output and input
digital signals, which may be audio signals, data signals or control
signals. Besides these interfaces, a mobile phone requires an interface
for supplying charging current. The mobile phone of the invention
is particularly advantageous when installed in a car, the hand-held
mobile phone being placed in a holder as an independently operating
mobile phone, integrated in a versatile car equipment, including
for instance a complete loudspeaker feature with an external loudspeaker
and a microphone, an interface to an aerial outside the car, interfaces
to external data and control signals, such as for instance a signal
detecting the state of the ignition switch, an external alarm control,
etc., and power supply from the car battery for instance.
Using several connectors in a single mobile phone naturally causes
additional expenses, occasionally involving laborious connection
of a number of lines. This conventional configuration has the additional
drawback of strict protective steps imposed by EMC (Electromagnetic
Compatibility ) requirements, both economically and technologically
speaking. Electromagnetic protection of the mobile phone lines shall
be provided by means of low-pass filters or band-pass filters at
the interface of the phone connector. The great number of interfaces
and connectors complicates the phone design considerably, calling
for several filter components in the phone and entailing laborious
and complicated manufacture. What is more, this kind of filter arrangement
requires space in the phone set and will thus increase the weight
and the size of the phone.
With some interfaces, for instance with a data interface, the transfer
rate will not comply with EMC requirements. In that case it might
be necessary to use an optical interface, which, again, requires
large space and separate operating voltage.
OBJECT AND SUMMARY OF THE INVENTION
The object of the present invention is to provide a mobile phone
interface and an interface arrangement that allow the drawbacks
and problems described above to be eliminated. A mobile phone comprises
an RF signal interface containing a connector over which input and
output RF signals pass on a coaxial line connected to the connector.
The mobile phone further comprises one or more interfaces for at
least some of digital input and output signals, comprising audio
signals, control signals and data signals, characterised in that
the digital signal interfaces are connected to the RF signal interface
such that the digital input and output signals are received and
transmitted through the connector included in the RF signal interface
on the coaxial line that is connected to the connector.
An interface configuration is disclosed for a mobile phone for
connecting the mobile phone to external output and input signals
that comprise external RF signals and external audio signals, control
signals and data signals. The interface configuration is characterised
in that an interface unit is connected to an end of a coaxial line
opposite to the mobile phone, the interface unit comprising means
for separating RF signals and digital signals received on the coaxial
line, means for receiving and separating digital signals coming
from the coaxial line and for transmitting digital signals to the
coaxial line, a physical interface for RF signals, and physical
interfaces for external input and output signals, comprising output
and input audio signals, control signals and data signals corresponding
to the digital signals. The interface configuration further comprises
means for processing and controlling external input signals passing
between the physical interfaces and the means for transmitting and
receiving digital signals into corresponding digital input signals,
and for processing digital output signals into corresponding external
output signals.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in further detail below with reference
to the accompanying drawings, in which:
FIG. 1 is a perspective view of a conventional mobile phone with
interface and connector arrangements for external signals and devices,
FIG. 2 is a schematic view of one embodiment of the mobile phone
of the invention including its interface configuration,
FIG. 3 is a schematic view of a second embodiment of the mobile
phone of the invention including its interface configuration,
FIG. 4 is a schematic view of an interface unit in one version
of the mobile phone interface configuration of the embodiment in
FIG. 2,
FIG. 5 is a schematic view of an interface unit in one version
of the mobile phone interface configuration of the embodiment in
FIG. 3,
FIG. 6 is a block diagram of one embodiment of the interface circuit
provided in the mobile phone of the invention and accordingly in
the interface unit and
FIG. 7 is a perspective view of the mobile phone of the invention
installed in a car.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 illustrates one embodiment of the mobile phone of the invention
with its interface configuration. The mobile phone 1 has an aerial
2 and a connector 3 for input and output RF signals passing through
the external aerial on a coaxial line 6 connected to the connector
3. A switch 7 is provided at the RF connector 3 and the aerial 2,
the switch disconnecting an internal RF signal line 8, 9 in the
phone from the aerial 2 and connecting it to the RF connector 3,
when the coaxial line 6 is connected to the connector 3. The connector
3 is primarily a coaxial connector, but it is possible to use a
different RF connector, which is say, symmetrical in some other
respect than coaxially, without significantly affecting the characteristics
of the interface in terms of EMC protection. The mobile phone electronics,
comprising for instance RF signal transmission and reception circuits,
including the entire signal processing associated with this, is
generally illustrated by the electronics segment 12, the line 9
for RF-IN/OUT signals at a frequency of the order of 900 MHz being
connected to this segment. FIG. 2 shows the speech/channel codec
14 and the main processor 15 as special segments in the electronics
segment 2.
In the mobile phone of the invention, digital input and output
signals, which may be audio signals, control signals and data signals,
are received and transmitted over the connector 3 and the coaxial
line 6. In the preferred embodiment of the invention, digital signals
are transferred on the coaxial line when modulated to a relatively
low-frequency carrier wave in the potential range of 1 to 5 MHz.
In principle, a higher frequency is also usable as a carrier frequency,
provided that it is clearly distinct from the radio frequencies
being transmitted. The line connected to the connector 3 over the
switch 6 branches into a RF signal line 9 and a line 10 for digital
signals, and the mobile phone comprises means 21, 22, 23, 24 and
25 for separating RF signals and digital signals. In the embodiment
of the invention shown in FIG. 2, these means include a capacitor
23 at the RF line 9 and a quarter-wave transfer line 21 and a capacitor
25 at the line 10 for digital signals, these means having been selected
with values such that digital signals modulated for a carrier wave
are conducted to line 10 and RF signals to line 9. The line 10 is
additionally provided with a resistance 22 and a capacitor 24, which
form a setting adapted to the carrier frequency concerned and filter
off any direct current components. It is obvious to those skilled
in the art that the embodiment described above is merely one of
several possible embodiments, and that the means for separating
RF signals and digital signals modulated to carrier frequency can
be carried out in many optional ways.
The line 10 for a digital signal is connected to an interface circuit
13, which is devised to receive and separate digital signals received
from the coaxial line 6 and accordingly, to transmit outgoing digital
signals to the coaxial line. FIG. 2 is a schematic view of connections
for various digital signals between the interface circuit 13 and
the mobile phone electronic block 12 including the speech/channel
codec 14 and the processor 15. These connections and signals may
comprise input or output data or control signals, D-IN and D-OUT
respectively, with corresponding lines 16 and 17 between the interface
circuit and the electronics segment 12. In a car installment, these
signals may consist for instance of a signal indicating the state
of the ignition switch as an input signal, or a control signal from
an external alarm as an output signal. Similarly, the lines 18 and
19 between the interface circuit 13 and the speech/channel codec
14 are intended for A-IN and A-OUT input and output audio signals.
A typical A-IN audio signal is for instance a signal obtained from
an external microphone, which is for the mobile hands-free function,
and transformed into digital form, e.g. a bit flow sampled into
8-bit words at a 8 kHz frequency, coded by the speech/channel codec
14 for the traffic channel to be transmitted. Accordingly, the A-OUT
output audio signal may be a similar bit flow to an external loudspeaker,
which the speech/channel codec 14 has formed by decoding the line
channel received. The digital signals transmitted on the coaxial
line also contain P-BUS control or data signals between the mobile
phone processor and external devices, which are received by the
mobile phone main processor 15 or transmitted by this on the processor
bus 20 between the interface circuit 13 and the processor 15. In
the operation of the mobile phone of the invention, the necessary
line between the main processor 15 and the interface circuit 13
also takes place over this bus 20. The parts and the operation of
the interface circuit 13 and the digital signal transmission with
the coaxial line 6 will be described in further detail below, in
the explanation of FIG. 6.
FIG. 3 illustrates another embodiment of the mobile phone of the
invention and its interface configuration. This embodiment comprises
a power supply, particularly charging current supply over a specific
connector 4 in the embodiment of FIG. 2, over the coaxial line 6
and the connector 3. To this end, in addition to the means in the
mobile phone 1 for separating RF signals from digital signals means
for further separating supply current from digital signals to the
supply current line 11 are provided. In the configuration shown
in FIG. 3, the means of the arrangement in FIG. 2 have been supplemented
with a choke coil 26, which prevents digital signals modulated to
carrier frequency from reaching the current supply line 11, and
a capacitor 27, which filters off any alternating current components
having remained in the supply current. It is obvious to those skilled
in the art that there are many other practical ways of separating
direct current from RF signals and digital signals than the ones
shown in FIG. 3. Apart from the current supply arrangement, the
operation of the embodiment in FIG. 3 is identical to that of FIG.
2.
However, in most practical implementations, it is not useful to
combine the current supply interface with the RF signal interface
and the digital signal interface. In the configuration in FIG. 3,
the choke coil 26 separating supply current from other signals will
be of a cumbersome mechanical size, given that high inductance will
be required, especially if the frequency of the other signals is
low. High inductance alone is not enough, a sufficient wire thickness
also being required for the supply current. Moreover, the ferrite
core of the coil must not be saturated with supplied current, otherwise
it might reduce inductance at the frequency of the other signals,
which, in turn, would have a negative impact on filtering. The large-sized
choke coil called for on the grounds set out above is not suitable
for a hand-held mobile phone, which is the mobile phone version
to which this invention is preferably applied.
For connection to external devices, the mobile phone of the invention
requires an interface configuration, in which means are provided
at the end of the coaxial line opposite to the mobile phone, which
carry out the same functions as do the interface circuit 13 of the
invention and the other connections of the embodiments in FIGS.
2 and 3 in a mobile phone. FIG. 4 illustrates one embodiment of
an interface unit usable in the mobile phone interface configuration
of the embodiment in FIG. 2. The interface unit 31 has a connector
33 for connecting the coaxial line 6, to which a signal line 38
is connected. The connector 33, as the connector 3, is principally
coaxial, but may be some other type of RF connector. The means 51,
52, 53, 54 and 55, corresponding to the means 21, 22, 23, 24 and
25 of the mobile phone in FIG. 2, are separated by RF signals and
digital signals. In addition, in interface unit 31, an inductance
59 has been connected to the RF line 39, the inductance forming
together with the capacitor 53 a high-pass filter, which serves
to prevent low-frequency signals from reaching the external aerial
32, for instance the external aerial of a car. The external aerial
32 may be connected to the interface unit 31 either directly or
over the connector 35. The interface circuit 43 performs the same
functions as the corresponding interface circuit 13 in the mobile
phone, and is connected to lines 46 to 50, corresponding to lines
16 to 20, for the same D-IN, D-OUT, A-IN, A-OUT and P-BUS signals.
These lines connect the interface circuit 43 with the electronics
segment 44, which among other components comprises a speech/channel
codec 42 and a main processor 45 corresponding to parts 14 and 15
of the mobile phone electronics segment 12. In this embodiment,
the electronics segment further comprises a current supply segment
58, which has a separate current supply line over the line 41 and
the connector 34 to the current supply connector 4 in the mobile
phone. The interface unit is provided with a physical interface
60 for current supply, to which one can connect power supply from
say, a car battery. The interface unit is also provided with physical
interfaces 61 for external devices, for instance an external microphone
and an external loudspeaker included in a loudspeaker feature, external
data equipment or external control interfaces.
FIG. 5 illustrates an interface unit, corresponding to the one
in FIG. 4, which is usable in the interface configuration of the
mobile phone of the embodiment in FIG. 3. The interface unit 31
in FIG. 5 differs from the one in FIG. 4 only in that it comprises
a path formed by the choke coil 56 and the capacitor 57, which,
alongside the components 51 to 55 for separating signals enables
direct current to be fed from the line 41 to the coaxial line 6.
The functions of the choke coil 56 and the capacitor 57 are equal
to those of the corresponding choke coil 26 and capacitor 27 in
the mobile phone pertaining to the interface configuration shown
in FIG. 3.
FIG. 6 is a schematic diagram of one embodiment of the interface
circuit of the mobile phone of the invention and of its interface
unit. As described above, the interface circuits 13 and 43, respectively,
serve to receive and separate digital signals received from the
coaxial line on the one hand, and to transmit digital signals to
the coaxial line on the other hand. In the preferred embodiment
of the invention, digital signals are bidirectionally transmitted
on the coaxial line in a message form. Messages may be transmitted
and received on the contention principle or the alternating principle.
The interface circuit in FIG. 6 is an interface circuit 13 suitable
for the embodiments of the mobile phone of the invention described
above, and the figure indicates the lines to the interface circuit
under the same references 8 and 16 to 20 as FIGS. 2 and 3. Line
8 is provided from the coaxial line to the interface circuit to
which there are also lines 16 and 17 for received and transmitted
D-IN and D-OUT data and control signals, lines 18 and 19 for received
and transmitted A-IN and A-OUT digital audio signals, and a processor
bus line 20 for P-BUS data and control signals of the processor.
The control circuit 71 controls signal transmission and reception,
and in doing this it communicates over line 20 with the main processor
15 (not shown in FIG. 6). For signal exchange with the processor,
the interface circuit 13 is provided with control and buffer means
77 for the processor interface. Signals to be transmitted are recorded
in the transmission buffer 72 and are transmitted from there over
the modulator 73 to the line 8. Signals from the line 8 are demodulated
in the demodulator 74 and are subsequently temporarily stored in
the reception buffer 75. For the control of incoming and outgoing
lines, the interface circuit 13 is provided with means 76 for identifying
the mode of the coaxial line and a line from these means to the
control circuit 71. The interface circuit 13 is also provided with
buffers 78, 79, 80 and 81 and with lines 16, 17, 18 and 19 for D-IN.
D-OUT, A-IN and A-OUT output and input digital signals. The interface
circuits 43 in the interface units of the interface configuration
embodiments illustrated in FIGS. 4 and 5 can be carried out with
components and operations identical to the ones described above.
FIG. 7 illustrates the implementation of the mobile phone and the
interface configuration of FIGS. 3 and 5 in a mobile phone installed
in a car. For external connections, the mobile phone is only provided
with a RF connector 3, connected to a coaxial line 6, for instance
a coaxial spiral wire as shown in the figure. An interface unit
31 has been connected to the car installation holder, in which the
coaxial line 6 is connected with the RF connector 33. As indicated
in the figure, the holder may be provided with physical interfaces
35 in the interface unit 31 for an external aerial, 61a and 61b
for an external loudspeaker and an external microphone included
in a loudspeaker feature, 61c for data and control signals and 60
for power supply from the car battery for instance.
With the mobile phone and the interface configuration as illustrated
in FIGS. 2 and 4, the phone and the car installation holder having
separate connectors 3 and 34 for power supply, the connectors 3
and 4, or 33 and 34, may be located near each other, being set up
such that the power supply line is connected to the coaxial line,
and the connectors at either end of the line are combined into one
single connector, connected with a single-step operation. This embodiment
has not been illustrated in the drawings.
It is obvious to those skilled in the art that the basic inventive
idea, i.e. receiving and transmitting various signals over a coaxial
line connected to a mobile phone, can be carried out in various
ways. A number of embodiments of the invention have been described
in detail above, yet it is evident that the invention is not restricted
to these embodiments, but may vary within the scope defined in the
accompanying claims. |