a third and a fourth stream is also realized due to the flowing possible variations if we use two frequency pairs low 0 and high 1 with two systems 1 0 0 1 0 0 1 1 logic low 0 and logic high 1 rules have to be defined for each of the additional data streams there are different possibilities to define highs and lows e g the third data stream becomes logic low 0 if the lower frequency becomes logic high 1 and the higher frequency becomes logic low 0 the third data stream becomes logic high 1 if the lower frequency becomes logic low 0 and the higher frequency becomes logic high 1 the fourth data stream becomes logic low 0 if the lower frequency becomes logic low 0 and the higher frequency becomes logic low 0 the fourth data stream becomes logic high 1 if the lower frequency becomes logic high 1 and the higher frequency becomes logic high 1 to get the same data transmission rate as with channel 1 and 2 the third and the fourth channel will be summarized if needed as illustrated in fig6 there are three systems in the communication arrangement allowing for six combinations of frequency pairs with the same data rate these are the three individual outputs see fig6 rps 1 pair 1 rps 2 pair 2 rps 3 pair 3 and the cross channel signals of between rps 1 and rps 2 pair.