Binary Modulated Bandpass Signaling OOK(On-Off Keying) Or ASK(Amplitude Shift Keying) BPSK(Binary Phase Shift Keying) FSK(Frequency Shift Keying)
Binary Modulated Bandpass Signaling OOK(On-Off Keying) Or ASK(Amplitude Shift Keying) BPSK(Binary Phase Shift Keying) FSK(Frequency Shift Keying)
OOK(On-Off Keying) Also known as ASK(Amplitude Shift Keying) Carrier OOK output Cos(2πft) A.m(t)Cos(2πft) Message m(t) Message 1 Unipolar Modulation Bipolar Modulation OOK output W MWW
OOK(On-Off Keying) ◼ Also known as ASK(Amplitude Shift Keying) Carrier Cos(2fc t) Message m(t) OOK output Acm(t)Cos(2fc t) Message 1 0 1 0 1 0 1 Unipolar Modulation Bipolar Modulation OOK output 1 Tb R =
OOK(On-Off Keying) OOK signal in time domain ■s(t)=Am(t)cos(2πf) PSD(Power Spectral Density) Conventional AM type ■ A 8 A sin(π(f-f)/R 8R π(f-f)/R fc 2R 2/Th
OOK(On-Off Keying) ◼ OOK signal in time domain ◼ ◼ PSD(Power Spectral Density) ◼ Conventional AM type ( ) ( )cos(2 ) c c s t A m t f t = fc 2R = 2/Tb 2 8 Ac 2 2 sin( ( ) / ) ( ) 8 ( ) / c c c A f f R R f f R − −
Detection of OOK Noncoherent Detection OOK in Envelope Binary output Detector Coherent Detection with Low Pass Filter Am(t)cos2(2πft) OOK in Binary output LPF s(t)=Am(t)cos(2πft) 3n0 cos(2πft)
Detection of OOK ◼ Noncoherent Detection ◼ Coherent Detection with Low Pass Filter Envelope Detector OOK in Binary output LPF OOK in Binary output cos(2 ) c f t ( ) ( )cos(2 ) c c s t A m t f t = 2 ( ) cos (2 ) A m t f t c c 1 ( ) 2 A m t c
Detection of OOK Coherent Detection with Correlator Optimum Receiver OOK in Sample Am(t)cos(2πft) & Binary Hold Out +n(t) cos(2πft) Clock From PLL From Bit sync logic Correlator output Comparator input Binary output
Detection of OOK ◼ Coherent Detection with Correlator ◼ Optimum Receiver Sample & Hold OOK in cos(2 ) c f t ( ) cos(2 ) ( ) A m t f t c c n t + From PLL 0 ( ) t d Clock From Bit sync logic VT Binary Out VT Correlator output Binary output Comparator input