IMPLEMENTASI LOW PASS FILTER PADA PEMBATAS BIDANG KOMUNIKASI SUARA UNTUK MENINGKATKAN KAPASITAS KANAL KOMUNIKASI

Abstrak

Audio Low Pass Filter on telephone and radio communication systems has a cut-off frequency of 4 KHz. This bandwidth is considered sufficient to "cut" the 20 KHz human vocal signal source. The need for communication channels is increasing but frequency allocation is limited. One method to increase the communication channel is "narrowed" the cut-off frequency of the Low Pass Filter. This study uses a 4-order Sallen and Key Butterwworth Low Pass Filter with cut-off frequency varying from 4 KHz to 500 Hz. At each cut-off frequency, speech recognition is performed, whether it can still be recognized. The results showed that cutting the audio signal with cut-off frequencies of 4 KHz, 3.5 KHz, 3 KHz, and 2.5 KHz, the signal can still be recognized, so that a bandwidth of 2.5 KHz x 2 is obtained. Analysis show that with a bandwidth of 5 KHz, the capacity of the communication channel is incresed by 66.67%.