First line: [AK2391] BASE BAND FILTER SHIFT QPSK MODULATION eral Description AK2391 band limiting filter shift QPSK modulation Personal Handy phone System (PHS) Japan. AK2391 compliant with Personal Handy phone System standard Japan. AK2391 consists logic, Root Nyquist-Roll-offfilters converters etc.Abstract: .. ASAHI KASEI [AK2391] AKM AK 2 3 9 1 BASE BAND FILTER FOR s/4 SHIFT QPSK MODULATION i G e n eral Description The AK2391 is a band limiting filter for n /4 shift QPSK modulation of Personal Handy phone System .. Tags: datasheet abstract..