GB1596195A

GB1596195A - Passenger-address and passenger entertainment system

Info

Publication number: GB1596195A
Application number: GB16131/78A
Authority: GB
Original assignee: Fieldtech Ltd
Current assignee: Fieldtech Ltd
Priority date: 1978-04-24
Filing date: 1978-04-24
Publication date: 1981-08-19

Description

(54) PASSENGER-ADDRESS AND PASSENGER ENTERTAINMENT SYSTEM (71) We, FIELDTECH LIMITED, a British Company of Heathrow Airport, Hounslow, TW6, 3AF, London, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to a combined passenger-address and passengerentertainment system particularly for aircraft, especially light aircraft including helicopters.

Combined passenger address (PA) and inflight entertainment (IFE) systems are known for large or long-haul aircraft. Such a system includes facility for running a plurality of tape cartridges simultaneously and multiplex equipment is used to enable each passenger to select, on'a control at his seat, which "channel" he wishes to hear.

The system includes PA facility, whereby a member of the crew may address the passengers: the PA, when used, stops all cartridges temporarily and transmits a chime (a high pitch note followed by a low pitch note) before the crew member delivers his address. This system is expensive and the equipment is both bulky and heavy and for all of these reasons is particularly unsuited to light aircraft.

Where a light aircraft is provided with both PA and IFE facility, the PA and IFE are entirely separate systems, so that if a crew member wishes to address the passengers, he must first remember to switch off the IFE system (the audio output of which is not extended to the flight deck).

This invention provides a combined passenger-address and passengerentertainment system installed in a passenger-carrier, comprising a tape cassette or cartridge deck for playing a single cassette or cartridge at a time, a plurality of audio speakers hard-wired directly to the cassette or cartridge audio output so as all to reproduce the programme recorded on the single cassette or cartridge being played, a microphone, means operable to interrupt the transmission of the recorded programme to the speakers and to enable instead the transmission of a passenger address from said microphone to the speakers, the transmission of said passenger address being otherwise disabled, and a chimesignal generating circuit which is activated upon operation of said interrupting means to relay a chime through the speakers, the system comprising two audio channels and arranged for the passenger address to be relayed over both channels simultaneously, and in which for the transmission of the recorded programme, the two channels are used as the two channels of a stereo system, the recorded programme being in stereo and the cassette/cartridge deck including stereo reproduction means.

An embodiment which is to be described herein is packaged within a panel mounted unit of 5.75 inch width, 3 inch height and 7.18 inch depth and weighs under 4 Ibs. The unit houses a cassette deck and all circuits and its front panel, includes its operating controls and associated indicating lamps.

The cassette deck taked standard music cassettes or specially pre-recorded cassettes with information on emergency procedures and/or flight safety briefings, for relay to the passengers. The unit is mounted on the flight panel and is operable by the crew. The system may also be used for playing cockpit check list information for crew use.

Pneumatic (stethoscope-type) headsets may be provided at each seat position and fed by the system, or distributed loudspeakers may be fed by the system. In the embodiment to be described, the system can drive up to 40 stereo headsets or 20 distributed loudspeakers. The capacity can be extended by 40 headset increments by adding further power amplifiers in-line, as additional units. One or two centralised loudspeaker units, with integral 20 watt amplifiers for example, can also be used.

The front panel includes a function switch in the embodiment to be described, for selection of ground/flight, audio levels and headset and/or loudspeaker operations.

Said embodiment will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a block diagram of the audio circuits and audio control circuits of the system; Figure 2 is a detailed circuit diagram corresponding to the audio control circuits of Figure 1; and Figure 3 is a block diagram of the power supply circuits of the system.

Referring firstly to the block diagram of Figure 1, a stereo cassette deck SCD is provided and the replay head RH feeds respective Pre-Amplifiers for the right hand and left hand channels. The outputs of the Pre-Amplifiers are passed through respective CMOS switches SW1, SW2 to respective Controllable Amplifiers and thence to respective Power Amplifiers and Output Isolation stages providing stereo audio outputs hard-wire to individual pneumatic, stethoscope-type headsets or to distributed speakers, and audio outputs hard-wired to centralised loudspeakers. A test switch S2 is provided on the control box, adjacent the cassette deck, and is operable from a rest position to either of two test positions in order to connect a Self Test Circuit to the output of either Power Amplifier.If there is an audio output present of the required level for the channel being tested, a Test Lamp LP1 is energised.

This is a means for the flight deck crew to test that the audio system is operating, for the entertainment is not permitted to extend to the flight deck.

A chime generating circuit, as described in our co-pending Patent application No.

16132/78 Serial No. 1596196, is provided.

This is activated when a Primary Key Line is activated (in a manner to be described herein). The Primary Key Line activates a Chime Timing circuit the output of which activates both a High Chime Oscillator and a Low Chime Timing circuit for a Low Chime Oscillator. The oscillator outputs are connected to a common Sine Shaper through respective Decay Circuits DC1, DC2, which are controlled by their respective Chime Timing circuits.

The Primary Key Line, when activated, is effective through a diode CR13 and over a Secondary Key Line to open the CMOS switches SW1 and SW2 to interrupt the passage of audio signals from the Pre- Amplifiers. At the same time, the Secondary Key Line is effective through an Inverter to close CMOS switches SW3, SW4 to enable audio chime signals issuing from the Sine Shaper, and amplified by a chime Amplifier, to pass simultaneously to both Controllable Amplifiers and thus to be reproduced in the speakers of both stereo channels. The chime comprises a high pitch note followed by a low pitch note.

An input as shown to the Low Chime Timing circuit, simultaneous with illuminating either a "no Smoking" or a "Fasten Seat Belts" sign, activates the Low Chime Oscillator without activating the High Chime Oscillator and the low pitch note alone issues from the Sine Shaper. At the same time the Secondary Key Line is activated for T second to open CMOS switches SW1 and SW2 (thus interrupting the entertainment which is being relayed) and, through the Inverter, to open CMOS switches SW3, SW4. The low chime alone is thus relayed during the T second for which the entertainment is interrupted. Diode CR13 prevents the Primary Key Line being activated at this time in response to activation of the Secondary Key Line.

The chime generating circuit and its operation is described in detail in our aforementioned co-pending Patent application No. 16132/78 Serial No.

1596196, and such description will not be repeated herein.

The Primary Key Line is activated when a crew member wishes to address the passengers. When he pushes the push-totalk button on his microphone, an input PTT is applied to a Key Relay RL1 and this activates the Primary Key Line for as long as the push-to-talk button is depressed. The Key Relay RLI at the same time provides a "Pause" output which is effective to stop the cassette deck drive motor and to maintain energised a solenoid which controls a mechanical latch for keeping the cassette in position against an ejecting spring bias. Details of a retention solenoid control circuit are given in our co-pending Patent application No. 16133/78 Serial No.

1596197. The Key Relay also provides outputs EXT and INT to energise indicator lamps exterior and interior to the unit.

The microphone used to address the passengers may be a microphone FP plugged directly into the front panel of the PA/IFE system or a microphone CA at a cabin attendant's position. The output of either microphone is applied to an amplifier MIC AMP, an output of which is passed through an Attenuator and simultaneously through both CMOS switches SW3, SW4 to the two channels for simultaneous relay. At the same time a low-level audio output LO is available from the MIC AMP for the crew.

The MIC AMP and LO audio output are connected into the crew's intercommunications system. Figure 1 shows two intercommunications microphones ICS Mic 1 and ICS Mic 2 connected to the MIC AMP to provide the LO audio output which is relayed to the intercommunications system. The MIC AMP output to CMOS switches SW3, SW4 is not relayed to the passengers except when input PTT is activated to close SW3 and SW4.

Referring to Figure 2, the circuit is shown in detail. The Pre-Amplifiers are omitted and the Controllable Amplifiers and succeeding stages are omitted, but the connections of these various circuits can be seen from the terminals El, E2 and E3, E4 shown in Figures 1 and 2. The chime-signal generating circuit is shown below the double chain-dotted line (except for the Sine Shape SS which is shown above) and reference should be made to our aforementioned Patent Application No.

16132/78 Serial No. 1596196, for a detailed description thereof. The Primary Key Line is shown at PL and the Secondary Key Line at K.

The Key Relay RCI comprises a solenoid, with parallel diode CR8, connected between the +28V supply and push-to-talk terminal E13, a capacitor C23 being connected between this terminal and ground. Operating the push-to-talk button connects E13 to ground to actuate the relay.

One relay contact disconnects "pause" terminal E9 from ground (disconnecting ground from the cassette drive motor) and connects Primary Key Line PL to ground (also connecting "Pause" terminal E8 to ground). A second contact connects ground to terminal El 1 and, through a diode CR12, to terminal E10 to energise interior and exterior cabin indicator lights which are connected thereto. A capacitor C10 is connected between El 1 and ground.

The Sine Shaper output is applied through a gain adjusting resistor R40 to one input of an operational amplifier OA5 forming the Chime Amplifier. The other input is connected to the junction between resistors R42 and R41 connected between a +12V supply and ground. The output of OA5 is applied through a capacitor C18 to the signal inputs of both CMOS switches SW3, SW4.

The Secondary Key Line K is connected through a diode CR2 to the control terminals of both CMOS switches SW1 SW2, a capacitor C26 being connected between these terminals and ground. The output of diode CR2 is also applied through a diode CR1 to the base of a transistor Q1 serving as the Inverter. The output on the collector of transistor Q1 is coupled through a 3.6V Zener CR3 to the control terminals of both CMOS switches SW3 and SW4. The Zener CR3 is in a series connection between + 12V and ground, of a resistor R6, itself and a resistor R36 with parallel capacitor C4 and ensures that, when transistor Ql is in its normal, conductive state, a sufficiently low voltage level is applied to the control terminals of CMOS switches SW3 and SW4 to hold them open.

A crew's intercommunications microphone, a cabin-attendant's microphone and the front panel microphone may be connected to terminals E5, E6 and E7 respectively. Terminals E6 and E7 are coupled to one input of an operational amplifier OA6 (forming the MIC AMP) through a capacitor C3 and adjustable resistor R3, terminal E5 being similarly coupled but additionally through a capacitor Cl. Bias for the other input of OA6 is provided at the junction of resistors Rll and R12 connected between +12V and ground. The output of OA6 is coupled through capacitors C5 and C2 to the LO audio output, and through capacitor C5, a resistor R5 and a capacitor C7 to the signal inputs of CMOS switches SW3, SW2.

The two operational amplifiers OA5, OA6 are provided together on a single integrated circuit marketed by Motorola Inc. under designation My 1458. The four CMOS switches are all provided on a single integrated circuit marketed under designation CD4016. The pin connection numbers are as shown in Figure 2.

Comparison of Figure 2 with the block diagram of Figure 1 and the description of operation given with reference to Figure 1 will serve as explanation of the operation of Figure 2. It will be noted that when the Key Relay RL1 is operated to connect the Primary Key Line to ground, ground is applied through diode CR13 to CMOS switches SW1, SW2 to open these and to inverter Q1 to close CMOS switches SW3, SW4. Normally switches SW1, SW2 are held closed by the +12V supply applied through a resistor R10 and switches STW3, SW4 are held open by ground applied to them through transistor Q 1. When, for single chime operation, the secondary Key Line goes to low voltage, with the Primary Key Line still open circuit, diode CR13 prevents this low being applied to the Primary Key Line.

Referring now to Figure 3, the aircraft supply (+27.5V d.c.) is applied through an ON/OFF relay, a fuse FS1 and a low frequency Ripple Filter to a 23V Regulator.

The ON/OFF relay is controlled by a Function Switch on the front panel, which in other positions enables respective loudspeakers or ground/flight communication. The 23V output from the 23V Regulator serves, through an audio frequency Band Stop Filter and respective fuses FS3, FS4, FS5 and FS6, the two loudspeakers and the two Power Amplifiers.

The 23V Regulator also feeds a first 12V Regulator U2 which serves all of the audio circuits, and a second 12V Regulator U3 (through a fuse FS2) which serves the Motor Speed Control for motor drive, and the retention solenoid control circuit of the cassette deck.

The supplies to the audio circuits, amplifiers and speakers are protected from electrical breakdowns in the motor control firstly by the 12V Regulator U3 and secondly by the fuse FS2.

It will be particularly noted that two channels are provided for passenger address, representing very important duplication to protect against malfunction of either. For IFE, the system makes use of the two channels as the two channels for relaying stereo.

WHAT WE CLAIM IS: 1. A combined passenger-address and passenger-entertainment system installed in a passenger-carrier, comprising a tape cassette or cartridge deck for playing a single cassette or cartridge at a time, a plurality of audio speakers hard-wired directly to the cassette or cartridge audio output so as all to reproduce the programme recorded on the single cassette or cartridge being played, a microphone, means operable to interrupt the transmission of the recorded programme to the speakers and to enable instead the transmission of a passenger address from said microphone to the speakers, the transmission of said passenger address being otherwise disabled, and a chime-signal generating circuit which is activated upon operation of said interrupting means to relay a chime through the speakers, the system comprising two audio channels and arranged for the passenger address to be relayed over both channels simultaneously, and in which, for the transmission of the recorded programme, the two channels are used as the two channels of a stereo system, the recorded programme being in stereo and the cassette/cartridge deck including stereo reproduction means.

2. A system as claimed in claim 1, in which the speakers include headsets for the individual passengers.

3. A system as claimed in claim 2, in which the headsets are pneumatic, stethoscope-type headsets.

4. A system as claimed in claim 1, 2 or 3, in which the speakers include distributed loudspeakers.

5. A system as claimed in any preceding claim, in which the speakers include centralised loudspeakers.

6. A system as claimed in claim 4 or 5, in which the distributed and/or centralised loudspeakers are enabled to receive the passenger address upon operation of said interrupting means.

7. A system as claimed in any preceding claim, comprising first switching means for disconnecting the audio output of the cassette/cartridge deck when said interrupting means is operated and second switching means at the same time effective to switch in the output of the chime-signal generating circuit.

8. A system as claimed in claim 7, in which the second switching means is at the same time effective to switch in an audio output from said passenger address microphone.

9. A system as claimed in claim 8, comprising an amplifier for said microphone, the output of said amplifier being connected through said switching means.

10. A system as claimed in claim 9, in which said amplifier has a separate low level audio output terminal.

11. A system as claimed in claim 9 or 10, comprising a flight-panel mounted unit with said microphone plugged into a front panel thereof.

12. A system as claimed in claim 10, connected to a crew's intercommunications system comprising microphones connected to said amplifier and speakers coupled to said separate low level audio output terminal.

13. A combined passenger-address and passenger entertainment system installed in a passenger carrier and substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Regulator U2 which serves all of the audio circuits, and a second 12V Regulator U3 (through a fuse FS2) which serves the Motor Speed Control for motor drive, and the retention solenoid control circuit of the cassette deck. The supplies to the audio circuits, amplifiers and speakers are protected from electrical breakdowns in the motor control firstly by the 12V Regulator U3 and secondly by the fuse FS2. It will be particularly noted that two channels are provided for passenger address, representing very important duplication to protect against malfunction of either. For IFE, the system makes use of the two channels as the two channels for relaying stereo. WHAT WE CLAIM IS:

1. A combined passenger-address and passenger-entertainment system installed in a passenger-carrier, comprising a tape cassette or cartridge deck for playing a single cassette or cartridge at a time, a plurality of audio speakers hard-wired directly to the cassette or cartridge audio output so as all to reproduce the programme recorded on the single cassette or cartridge being played, a microphone, means operable to interrupt the transmission of the recorded programme to the speakers and to enable instead the transmission of a passenger address from said microphone to the speakers, the transmission of said passenger address being otherwise disabled, and a chime-signal generating circuit which is activated upon operation of said interrupting means to relay a chime through the speakers, the system comprising two audio channels and arranged for the passenger address to be relayed over both channels simultaneously, and in which, for the transmission of the recorded programme, the two channels are used as the two channels of a stereo system, the recorded programme being in stereo and the cassette/cartridge deck including stereo reproduction means.