FR2487608A1 - Portable phase modulation duplex transceiver - has common aerial coupled to transmitter and receiver through isolating duplexer having cell structure - Google Patents

Abstract

The appts. operates with the transmission and reception frequencies in the same bond and with the same separation as a semi-duplex system using a duplexer (6) to provide 50dB isolation between transmitter and receiver with only 1.3dB loss. The duplexer (6) is made of aluminium and is divided into four identical cells (7,8) closed at opposing ends by two brass plates. One plate supports a mandrel in each cell in turn supporting a helical wire coil (21-24) series soldered with an adjustable brass screw-threaded stud (12) supported in the opposing brass plate. The cells serve as passband filters and rejection circuits with a pair in each of the receiver and transmission lines coupled to a common aerial (11). The coils of each pair are interconnected at a low impedance tapping by a quarter wavelength coaxial cable.

Description

 The present invention relates to the field of portable, duplex, phase modulation transceivers operating in the same frequency band.

Currently, various modes of radio transmission, using portable, exist - the simplex, that is to say the transmitter and receiver tra
operate on the same frequency and where a switching system
tion is used, allowing either to be in transmission position,
either in reception position.

In the current technique, this operating mode does not
not allow to go through a relay.

- half-duplex, that is to say, transceivers using
the same switching means as the simplex but where the fre
resignation and reception quences are different, this in
the same frequency band.

For example, in the 146-174 MHz range, standardized in France,
the difference between the transmission frequency and the re frequency
this is 4.6 MHz.

Hence the main advantage of this operating mode
allow the use of a relay station.

- duplex: this operating mode allows deletion
of the switching system and thus allows two interlocu
tutors to converse simultaneously.

In the current technique, for transceivers por
duplex, a transmission frequency and a frequency are used
reception frequency in different frequency ranges.

(For example, 40 MHz and 80 MHz) This does not allow integration
of these transceivers in half-duplex networks.

 The present invention is the creation of a portable device; dup] ex, working in the same frequency band for transmission and reception, with the same frequency difference as half-duplex. This therefore allows its integration in half-duplex and duplex networks, including mobile and fixed transceivers, work with the same frequency difference between the transmission frequency and the reception frequency as half-duplex transceivers.

 The present invention is characterized by the use of a duplexer. By duplexer is meant a device making it possible to adapt a transmitter and a receiver to a common element of the antenna, this making it possible to work in the same frequency band.

The present invention is set out in the following with reference to the single board, located in the annex.
It consists of a metal enclosure enclosing four separate parts carefully mechanically partitioned.

1- An omission part (2) comprising all the organs of an issue
classic phase modulation, radio-telephone type and
a regulation system (5).

 Particular care is taken with its spectral purity.

The transmission power can be between a few thousand
liwatts and several watts, taking into account the range to be achieved
and the capacity of the voltage source.

2- A reception part (4) comprising a modulation receiver
phase, conventional double frequency change, genre ra
dio-telephone, and a regulation system (5).

3- The duplexer (6). The essential element of the present invention
is the duplexer. What is meant by duplexer (6) is a
set of very selective filters integrated in a metric box
canonical (6) and comprising two independent branches (9,10),
joined to a common element: the antenna (11).

a- an emission branch (9) starting from the antenna (11) and abou
weaving at the transmitter (2), through various cells (8).

b- a reception branch (10) starting from the antenna (11) and a
terminating, through various cells (7), at the entrance to the
receiver.

 Each cell has a filter.

In a duplexer, three current filter techniques are
likely to achieve the desired result: act
ner the receiver (4) and the transmitter (2) without alteration note
ble of the specific characteristics of each of these elements.

a-.a technique using rejector filters in
which said filters, in the emission branch (9), have
aim to reduce voltage at frequency as much as possible
received by the antenna (11), at the output of the transmitter (2) and
to let the voltage pass at the frequency of the transmitter
(2) moving towards the antenna (11).

.a technique using rejector filters in
which said filters, in the reception branch (10),
aim to relieve aw maXLim tension & frCqun-
ce supplied by the transmitter (2), at the receiver (4), and
to let the voltage pass at the receiving frequency cap
ted by the antenna.

b-.a technique using bandpass filters in
which said filters, in the transmission branch (9), do not
let through, without significant loss, that the tension at the
frequency produced by the transmitter (2) moving towards
antenna and eliminate all other voltages as much as possible.

.a technique using bandpass filters in
which said filters, in the reception branch (10), do not
let through, without significant loss, that the tension at the
frequency picked up by the antenna (11) moving towards the
receiver (4) and eliminate as much as possible all other tensions.

c- a technique using the combination of the two tech
above described where the adjustment and
point are delicate.

The duplexer used in the present invention uses the technique of rejector filters.

It consists of an extruded aluminum block 114 mm long, 34 mm wide and 34 mm high.

In this block, four cells (7.8) are arranged, each measuring 20mm side and 54mm long. This aluminum block is closed, at each end of said cells, by a brass plate fixed by tapped screws in the said block
Each brass plate has a specific function. The first plate is used to support the adjustment elements (12,13) of the various cells (7,8), these each comprising a rejector filter. The adjustment of each filter is materialized by a threaded rod (12) made of brass, screwed through said plate and locked by a lock nut (13).

The second plate serves as a support for four mandrels. Each mandrel is the support for a winding (21,22,23,24), called "helical coil", which is joined and welded at one end, on the so-called cold side, of said plate, the adjustment element (12) mentioned above coming to plunge inside said coil. This allows adjustment of the capacitive type.

A coaxial line, auart wave (25), joins the bolinaes
(Z1,> 2) at a low impedance socket, cold side, of each
these said coils (21,22).

Ts windings 22 and 2j are connected via a
quarter-wave coaxial line (26,27), starting from each of
low-impedance and smoothing sockets in common (28),
where the antenna (11) will be connected.

A quarter uncle coaxial line (29) joins the coils
(23) and (24) to a low impedance socket, cold side of each
of these said coils (23,24).

Just plug in, at the low impedance points of the bo
hoes (21) and (24), a 50 # coaxial cable (30,31) connecting
each of the elements: transmitter (2), receiver (4).

Each branch (9,10) can be send or receive.
branch is assigned to the highest frequency at trans
put, the other at the lowest.

The coaxial lines, quarter wave, (25,26,27,29) are made
using 50fr coaxial cable
According to this technique, an insulation of about 50 DB is ob
held between the transmitter (2) and the receiver (4) and vice versa,
for a loss of 1.3 DB, for the frequencies to be transmitted.

4- A voltage source part (20) .The use of batteries, bat
lead free (maintenance free and waterproof) or cadmium batteries
nickel is possible.

When using batteries, an opening allows
as the change of the batteries will be practiced in the case of
said invention. A socket will be placed on the case of
way to charge the battery or rechargeable batteries in
the case of their use.

Here now the appendices of the present invention
- a single switch (14) comprising 3 positions (stop, reception, transmission-reception)
- a test of the voltage source (15)
- a socket for the connection of an external microphone (16) with
internal microphone cut-off (17)
- a built-in speaker (18)
- a headphone socket (19) with cut-off of the interior speaker
There are two possible uses for these elements.
internal microphone (1) and the loudspeaker (18) in the case of a connection with a half-duplex network, the operator of the said invention being able to keep their hands free. 0n uses the external microphone jack (16) and the headphone jack (19) in the case of a link with a duplex network.

Other combinations of use are possible. Many accessories can be integrated into the present invention: selective calls, telephone dialing device, etc.

What care should we give to the construction of the said invention?
- great care for high frequency decoupling, at the input of
external elements (example: microphone and headset), on the wood
tier, must be brought, as we must not forget
it is a portable and the antenna radiates a high voltage
important frequency. This is picked up by all the elements
external (example: headphone and mid power leads
cro)
- On the other hand, the mechanical construction of the entire
said invention must be perfectly electrically connected to the
high frequency point of view. Otherwise, spitting would be per
receivable on transmission and at reception.

- The part "final stage of the transmitter" must be able to function
in permanent emission. for that, one must arrive at a good
cooling of the elements making up the said stage.

- High frequency decoupling inside the said invention
power supplies for each element.

- Each of the parties, transmission (2) and reception (4), must com
take a regulator (3,5) so as not to affect the function
each of the parties involved (example: dia
speech between reception modulation and sound modulation
The parties must disassociate themselves from the various
internal impedances of the various possible voltage sources.

The present invention is capable of having the following industrial applications
- This device, in semi-duplex networks, allows a user
sator provided with it to converse, having no handling
pulation to execute, that is to say, while remaining free,
with a contact person equipped with a half-duplex device.

- In the field of radio broadcasting and television, no-
duplex transceiver, portable, can be used as
means of transmission between a ringing tone on an eve-
already existing technical support (car or motorbike
reportage).

Other applications in the field of personal safety and in the field of precise and dangerous handling can be envisaged.

Claims (8)

IV0NDICAP IONS  1- Duplex, portable, phase-modulated transceiver station, the transmission frequency and reception frequency of which are in the same frequency band, characterized by the use of a duplexer making it possible to adapt the impedance of a transmitter and a receiver to a common element: the antenna, to eliminate in the receiving branch the voltage at the frequency produced by the transmitter, to eliminate in the sending branch the voltage to the frequency of the receiver adapted by the antenna.  2- transceiver station according to claim 1 characterized by the use of mechanical cells each containing a rejector filter with its adjustment element.  3- transceiver station according to claim 2, characterized by the use of several cells connected together by coaxial line, quarter wave.  4- transceiver station according to claim 3, characterized by the use of an unequal number of cells in each of the two branches, transmission and reception.  5- transceiver station according to claim 4, characterized by the use of cells mechanically connected or not.  6- transceiver station according to claim 2, characterized by the production of rejector filters, according to the technique known as "helical coil".  7 transceiver station according to claim 3, characterized by the use of flexible 50lit coaxial cable, semi-rigid or rigid, for the manufacture of a coaxial line, quarter wave, connecting each cell.  8- transceiver station according to claim 7, characterized by the use of coaxial cable of other impedance, flexible, semi-rigid or rigid.