Compact disc: pocket vanity

1987/08/01 Barandiaran, Xabier Iturria: Elhuyar aldizkaria

• Hardwarea

The bowels of a Philips CD10. The CD150 needed a complete integrated circuit (dark cross) to control the movement of the reader arm. Now only three microprocessors (dark circles) are needed. The numeric filter and the analog/numeric decoder are grouped into two microprocessors (clear circles). Before, four (clear crosses) were needed.

In a few years the compact disc vanity has been miniaturized and has become portable. However, its prices (75,000 pts.) It is also portable.

Miniaturization has been the most important step in the development of CD players. The compactors were born in 1983 and besides weighing 15 kg, they had measures of 45 x 32 x 15cm. In three years they have decreased dramatically. Technics SL-PX5, for example, weighs 480 g and measures 126 x 126 x 23 mm. The quality music of this portable device has lost nothing and is equivalent to the fixed household appliances.

To achieve this type of compactness we have worked in three areas: mechanics, electronics and electronic feeding. The electronics of the devices have taken advantage of the advance in the integration of microprocessors and circuits. Today there are five circuits that once worked fifteen. Also, two groups of two first microprocessors controlled the radial and vertical movement of the arm. Currently this work is performed by a single microprocessor. The analog/numeric decoder and the numeric filter are grouped into two integrated circuits, for which the first four were needed.

1. Pionner PDC 7
2. Funai CDP 760
3. Grundig CDP 50
4. JVC XLR 10
5. Philips CD 10
6. Toshiba XR-P9RC
7. Sony D 50 MK II
8. Sony D 55 T

In this case, as in other portable electronic devices (calculator, magnetophone or walkmans), the biggest and heaviest element is that of power supply. In all appliances, their weight is at least equal to the rest.

Although their dimensions are small, these tools have many functions and the same functions as household appliances: pause, quick search, backward and forward zone jump, programming and repetition. Some also work as radio receivers.

Let it be a little expensive!