41. The control channels use signalling at 1, 200 bits per second with fast frequency shift keying ( FFSK ) subcarrier modulation. 42. The voice was keyed to two 16-inch vinyl phonograph records that contained a Frequency Shift Keying ( FSK ) audio tone. 43. Emission theory asserts that Doppler shifting of light from a moving source represents a frequency shift with no shift in wavelength. 44. Speech sounds also have duplicable higher-order characteristics such as rates and shape of modulations and rates and shape of frequency shifts . 45. �lectricit?de France ( EDF ) developed a system called " spread frequency shift keying " or S-FSK . See IEC 61334. 46. This frequency shift is not a Doppler shift, but is rather an optical cavity resonance effect, as explained below in Ring lasers. 47. Any Doppler frequency shift on the received signals will degrade the ripple cancelation process and this is discussed in more detail next. 48. The second term represents the frequency shift in the photoacoustic wave due to the motion of the absorbers observed by the ultrasonic transducer. 49. For measurements of chemical forces the effect of the long range van der Waals forces must be subtracted from the frequency shift data. 50. As the article currently stands we engage the reader from the perspective that there are many ways to explain frequency shifts observed in nature.
