1959 - History of Ericsson - History of Ericsson

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Fig. 3 Grouping of components in width Fig. 4 Grouping of components in depth Fig. 5 X 2397 Omnidirectional principle — a step towards the final solution 110 A broad grouping of the components is shown in fig. 3. This design is very similar to the previous loudspeaking telephone, but was considered unsuitable since its breadth would block an unnecessarily large part of the desk area behind it. An attempt at grouping of the components in depth is shown in fig. 4. This was no more satisfactory, however, owing to the exaggeration of a single dimension. A vertical grouping of the components (fig. 7) brought out the essential character of a loudspeaking telephone compared with an ordinary telephone, namely, that it should be heard in all directions. Previous types of loudspeaking telephone have not been true to character in this respect, but transmit and receive sound principally in one direction. This is also revealed by the methods of loudspeaking telephone measurement employed hitherto. At this stage of the work it was decided that the loudspeaker and microphone should be so placed that the sound would be reproduced as equally as possible in all directions. This omnidirectional function should be emphasized, furthermore, in the very design of the case. A vertical grouping was open to the same criticism as the other two concepts, that an exaggeration of one dimension makes the instrument unduly voluminous. Finally, a more concentrated, cubiform shape was tried out, in which no dimension unduly overshadowed the others (fig. 6). In the sketch stage the type emerged as a development of the vertical grouping idea. It was considered that the final solution should be along these lines. Fig. 6 x 7751 An approach to the final solution
Fig. 7 X 7750 Vertical grouping of components X 7752 Fig. 8 X 7753 Studies in circular design The following points had now become clear: the new instrument should be omnidirectional and of concentrated shape. The technical method of providing the omnidirectional property still remained an unsolved problem. For a time the development work was diverted into unprofitable channels. A shallow circular form of loudspeaker proved to offer an apt solution to the omnidirectional problem. Placed in the base of the instrument and with a resonance box about 15 mm high, it was made to transmit backwards (fig. 5). This was an important step towards the final solution. The Case Studies of the most suitable form for the case were for a time concentrated to circular shapes (fig. 8). In the illustration the microphone is placed centrally in the top of the instrument and the loudspeaker in the base with the slots arranged round the low, circular envelope. This theoretically ideal form 111
Page 1: 4 1959
Page 4 and 5: Ericovox, the One-Piece Loudspeakin
Page 6 and 7: Fig. 3 X 8156 Block schematic of co
Page 8 and 9: Fig. 5 x 8163 The Ericovox, L M Eri
Page 10 and 11: Fig. 8 X 2443 Sending frequency res
Page 12 and 13: 108 The Ericovox meets the requirem
Page 16 and 17: Fig. 9 X 8132 Case with pyramid-sha
Page 18 and 19: Fig. 12 X8134 Instrument with base
Page 20 and 21: Fig. 18 X8135 The locations of the
Page 22 and 23: Gothenburg Automatic Transit Exchan
Page 24 and 25: Fig. 3 x 8181 Block schematic of gr
Page 26 and 27: Fig. 6 122 x 8180 Block schematic o
Page 28 and 29: Fig. 8 X 2472 Link circuits for ori
Page 30 and 31: Fig. 10 X8182 Traffic supervisor's
Page 32 and 33: Fig. 2 X8167 Relay switchboard AMD
Page 34 and 35: 130 Priority The switchboard is des
Page 36 and 37: Crossbar Exchange Installed on Larg
Page 38 and 39: L M Ericsson to Undertake First C.T
Page 40: The Ericsson Group Associated and c

1959 - History of Ericsson - History of Ericsson

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