11. They are encoded separately just like they were in an amplitude-shift keying ( ASK ) modulator. 12. The tone is modulated using frequency shift keying . 13. Routines in the ROM were used to encode and decode data in frequency-shift keying for the cassette. 14. A frequency shift keying ( FSK ) signal is alternating between two waveforms, and allows passband transmission. 15. The uplink uses frequency-shift keying with 3.951 MHz for a logical'0'and 4.516 MHz for a logical'1 '. 16. Two bits of information is encoded into each state using a method known as quadrature phase-shift keying . 17. BPSK modulation has been replaced with newer modulation schemes such as QPSK ( quadrature phase-shift keying ). 18. It used Frequency Shift Keying ( FSK ) to send data, shifting between 20 kHz and 26 kHz. 19. When differential encoding is used in this manner, the scheme is known as differential phase-shift keying ( DPSK ). 20. The 145.947 MHz downlink, which uses binary phase-shift keying , also provides a datarate of 1, 200 bits per second.
