Currently, digital audio source such as a compact disk (CD) and a digital audio tape (DAT) has come to be mounted in cars to complement the sophisticated audio system . To mount these new functions in the limit set space, however, the conventional source such as the FM/AM tuner must be built more compact and lightweight.
On the other hand, to view the FM/AM tuner perspective from the standpoints of set design and manufacture, there are various problems such as given below.
Set variations are flung from those for the U.S.A. and Europe to those for Japan. It is difficult, if not impossible, to design the set designer for each of these set variations because of the limited designer availability.
Also, amid the tendency for world production base to be spread and increasingly numerous, high quality level is of the utmost importance for audio sets no matter where are manufactured.
This paper describes an effective solution to these problems.
First, to meet the needs for space saving, a radically new IC has been developed. This new IC dispenses with various external parts otherwise required for conventional FM/AM tuner systems and incorporate sophisticated IC design. The said IC consists of two system ICs to minimize the occupancy area of printed circuit board for realization of labor saving through dispersed arrangement.
To cope with the ever increasing number of set design processes and to make the production of high quality audio sets at increasing widespread production bases, a new FM/AM tuner system that requires a minimum of alignment has been successfully designed, using a D/A converter in the otherwise computer control section and eliminating the troublesome manual adjustment with the data stored in the EPROM controlled by means of a dedicated bus control system via a control micro computer.
In this new design, the D/A converter should be optimally pre-aligned at the stage of alignment through specific bus control.
As a result, the problem of undertaking each set design for each different shipping country or area has been solved by preparing software capable of controlling the specific bus control alignment.