Title of Invention:
Field configurable mike and audio circuit for UHF
communication system.
2. Field of invention:
The invention relates to the field of electronic system more
particularly to a switching mechanism, which incorporates the
realisation of mike input and audio output impedance to
implement the concept of field—configuration.
4
3. Background of Invention:
In the conventional mike input and audio output impedance
circuit methodology requires diflerent impedance levels to match
the headset configuration. A single circuit is designed for particular
value of impedance and in case of multiple impedance, addition of
new circuitry/ functionality on a PCB requires total re-design of the
PCB in order to meet required functionality. Further, in order to
utilise the same system in different aircraft that require different
impedance, redundant circuits are to be designed {0 meet
functionality which incur cost and time. The re-layout procedure of
the proven configuration is challenging and composes of:
o Placement of additional components 85 relocating existing
ones.
I
It Modification of PCB routing which may lead to unwanted
risks of colossi talk due to the redundant circuit.
By Anticipating the future scope, catering the redundant circuit in
initial design is not economical. This results in increase in size 85
complexity in the form of increased number of PCB design iterations, which further impact in increasing turnaround time
(TAT) and cost of the development.
The other challenge encountered is during the qualification testing
of the avionics equipment. Tests are required to be repeated
V
because of changes in mike input and audio output circuits. This
will lead to increased cost of the unit. Hence there is a need for a
mechanism that shall overcome the problems listed as above. The
new mechanism will overcome these difficulties without any
additional hardware modification and also serves as a cost elective
solution.
.
3.1Prhr Art
U82012325630A1: Nano/ Micro Electro-Mechanical Relay
A nano/ micro electro-mechanical relay, comprising an at least one
normally open (NO) mane/micro relay switch and an at least one
normally closed (NC) nano/ micro relay switch. Both the NC
mane/micro relay switch and the NO mane/micro relay switch can
be switched between their respective normal relay switch positions
and their respective actuated relay switch positions. An at least
.one nano/micro actuator including an at least one piezoelectric
stack layer being attached to an at least one elastic layer, wherein
the at least one Piezoelectric stack layer contracts to deflect the at
least one elastic layer, and thereby actuate the at least one
nano/ micro contact bar to simultaneously switch the NC
mane/micro relay switch and the NO nano/micro relay switch
between their respective normal relay switch position and their
respective actuated relay switch positions.
The above invention is purely about relay mechanism with a
switching functionality Without mention about how to meet the different impedance requirements Whereas the present invention is
an application based on electro mechanical relay coupled with a
transformer for selective impedance network.
CN106060716A: Audio mike switching module applicable to
financial self-service terminal equipment
The invention relates to an audio mike switching module applicable
to financial self-service terminal equipment, relating to the field of
financial self-service terminal products. A power amplifying unit,
an audio switching unit and a control processing unit are
integrated in the switching module, communicated with an upper
computer through a serial interface, and furthermore, respectively
interacted with an audio mike channel and a telephone handle
audio Line outlive Mic in channel; an onboard Program in
software version realises switching between the telephone handle
audio Line out/mike line in and an external audio mike channel
through upper computer software; an onboard program in
hardware version realises switching between the telephone handle
audio Li fie out/ mike line in and the external audio mike channel
by picking up and down a telephone handle; therefore, the overall
intelligent design of the self-service terminal equipment is
improved; the audio mike switching module is convenient to
operate; and the safety degree of a call content between a user and
a bank worker is improved. .
The above invention is applicable tq financial self-service terminal
equipment that switches between the Audio Line out and Mike In
through software logic whereas the present invention is applicable
to avionics. The above invention comprises of power amplifying
unit, audio switching unit and control processing unit Whereas the present invention comprises of electro mechanical relay and a
transformer to achieve required functionality.
CN114827838A: Audio signal output control method, output
circuit and switching circuit
The invention discloses an audio signal output control method,
an output circuit and a switching circuit, and .
the output switching circuit comprises a plurality
of audio signal output circuits. And connecting a third output pin
of the
'
NAND logic gate in the
previous audio signal output circuit with a second input pin of the
NAND logic gate in the next audio signal output circuit A plurality
of audio signal output circuits are connected in a nested manner,
and based on the use characteristics of an NAN D logic gate device,
when a plurality of audio signals are input in the circuit, only
one audio signal is selected to be output, and the rest audio signals
are muted. The scheme does not need to introduce MCU software
for control, is not limited by channel number switching, and i§
simple in structural design and easy to implement.
The above invention acts like a multiplexer which gives only one
audio output. It comprises of plurality of audio signal output
circuits with built-in NAND gates. Th? present invention is not a
multiplexer and it does not contain any NAND gates. Hence it is
different from the above invention.
In view of above cited prior arts, it is difficult for a person skilled in
art to arrive at the solution to the problems reported to the
background of invention.
Brief summary of Invention
A method is devised where in, a field configurable mike input
and audio output circuit is designed with a scope: for field configurable
features. An electro mechanical relay which operates
on 28V DC and with an open/ ground logic signal is used to switch
mike input impedance and audio output impedance between 150
ohms and 600 ohms. In normal condition the switch connects mike
input to first half split winding of transformer which provides 150
ohms impedance. When the control command comes from aircraft
the switch connects second half split winding of transformer which
provides 600 ohms impedance.
In audio circuit, the switch connects first half split winding of
transformer which provides 150 ohms impedance in normal
condition. When control command comes from the aircraft the
switch connects second half split winding of transformer which
provides 600 ohms impedance.

Claims
We claim,
1. A Field configurable mike and audio circuit for \UHF
communication system comprises of:
i. A Mike circuit characterised with an electro-mechanical
relay-1 (l) which operates on 28V DC and with an open/
ground logic signal, an attenuation (2) to limit the mike signal
level for 150 ohms in the selective channel line and a
transformer-1 (3) with primary winding and split secondary
winding. ‘
ii. An Audio circuit characterized with an 'amplifier (5), a
transformer-2 (6) with primacy winding and split secondary
winding and an electro-mechanical relay-2 (7) which operates
on 28V DC or ground signal.
2. The electro-mechanical relay-1 (l) and electro—mechanical
relay-2 (7) in open logic condition deselection of 150 ohms
impedance of transformer (3) 8s transformer-2 (6) respectively
and during ground logic condition provide selection of 600 ohms
impedance to the said transformer terminals.