GB1275761A - Improvements in and relating to electronic display arrangements - Google Patents

Abstract

1275761 Cathode-ray tube displays RICOH KK 9 July 1969 [15 July 1968] 34490/69 Heading H4T In an arrangement for displaying a plurality of symbols in a single line on the screen of a cathode-ray tube the symbols are produced during a plurality of successive horizontal seams by the selective application to the vertical beam deflection means of one or more of a plurality of, different, available waveforms, together with, beam bright-up pulses, the symbols being synthesized from the traces produced during each line scan. In the embodiment described four synchronized waveforms are utilized comprising as shown in Fig. 1; a train of regularly spaced semi-sinusoidal waves a; a full-wave rectified sinusoidal wave b of three times the frequency of wave a; a sawtooth wave c and a sawtooth wave d of three times the frequency of wave c. The generator of these waveforms includes matrix means which determine the levels L0-L4 (see Fig. 3) and amplitudes of “, ¢ and ¥ and the whole operation is controlled by clock pulses e. The symbols may comprise Alpha-Numeric characters including Japanese characters as shown in Fig. 2 and Fig. 3 shows the manner in which three characters are synthesized during four horizontal line seams SC1-SC4 during each of which the beam is deflected vertically by a selected one of the available waveforms in various magnitudes and polarities and by signals determining the levels L0-L4. A maximum of four vertical deflections is sufficient for any of the symbols shown in Fig. 2. In the general operation of the arrangement digital signals defining a single line of characters are recirculated four times in a register on the occurrence of every eighth clock pulse and on each circulation an output is derived which selects the deflection and blanking requirements for the particular horizontal "slice" of the line of characters (Fig. 4, not shown). Instead of the waveforms shown in Fig. 1, other waveforms including circular and trapezoidal may be employed.