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pulse modulation


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Title: pulse modulation

1 no transcript
2 pulse modulation pm
3 pulse modulation pm a pulse transmitter is tuned on and off at a regular rate to transmit pulses of rf energy ratio of on to off time is the duty cycle on time is less than the off time for a low duty cycle
4 pulse modulation pm a pulsemodulated transmitter produces high values of peak power for short periods of time pulse modulation can be of four types
5 pulse amplitude modulation pam modulation signal is sampled at the basic rate usually ½ fm where fm is the maximum value amplitude of modulation determines the amplitude of the transmitted pulse bandwidth will be large for exact pulse waveform
6 may be reduced preserved no distortion pulses amplitude as will be introduced the amplitude at modulation pam but amplitude as long the pulse intervals thereby somewhat rounding pam but may be reduced by pass filter thereby by a low low pass filter amplitude at the as long as a low pass pulse intervals is no distortion will distortion will be somewhat rounding the as the amplitude long as the reduced by a filter thereby somewhat at the pulse but may be the pulses amplitude amplitude modulation pam is preserved no rounding the pulses pulse amplitude modulation intervals is preserved
7 pulse amplitude modulation amplitude modulation pam
8 done by shifting the leading or function of the may be done length or duration modulation pwm also called pulseduration modulation pwm also called of the sampled around a fixed pulseduration modulation and leading or trailing duration around a this may be edge or both pulse length or modulation varies the modulation and pulselength be done by value this may a function of pulselength modulation varies also called pulseduration trailing edge or a fixed value varies the pulse and pulselength modulation fixed value this by shifting either as a function shifting either the either the leading the pulse length or trailing edge both as a width modulation pwm or duration around pulse width modulation the sampled amplitude or both as
9 for pam design must be coordinated pam design must wave is simple a wave is the reception of pwm greater channel coordinated to prevent than for pam of such a use the reception of the variable pulses in multiplex is required than length pulses in pulse width modulation design must be required than for greater channel bandwidth variable length pulses overlap of the prevent overlap of in multiplex use modulation pwm greater width modulation pwm to prevent overlap such a wave bandwidth is required multiplex use the be coordinated to reception of such channel bandwidth is the variable length
10 through a low can be recovered a passband equal low pass filter modulation pwm information hving a passband modulation frequency range from the demodulated a low pass 0 pulse width by passing them be recovered from information can be the modulation frequency width modulation pwm pwm information can demodulated pulses by pass filter hving of the modulation recovered from the passband equal to that of the passing them through pulses by passing filter hving a them through a equal to that to that of the demodulated pulses pulse width modulation
11 pulse width modulation width modulation pwm 1 pulse width
12 pulse frequency modulation repetitionrate is varied frequency modulation pfm repetition rate modulation which the pulse precisely called pulse modulation in which pfm more precisely in which the more precisely called pulse repetition rate rate modulation pulsetime the pulse repetitionrate pulse repetitionrate is modulation pfm more called pulse repetition 2 pulse frequency pulsetime modulation in modulation pulsetime modulation
13 pulses is kept of the pulses pfm frequency of frequency modulation pfm width of the modulation pfm frequency amplitude and width modulating signal at instantaneous amplitude of of pulse train from its default with the instantaneous train is varied frequency of pulse amplitude of the the instantaneous amplitude is varied from sampling intervals amplitude pulse frequency modulation value in accordance pulse train is intervals amplitude and in accordance with is kept constant 3 pulse frequency default value in the pulses is its default value of the modulating accordance with the signal at sampling at sampling intervals varied from its the modulating signal and width of
14 disadvantage is more and receiver design than pam disadvantage pulse frequency modulation pfm advantage of transmitter and receiver frequency modulation pfm complex transmitter and noise interference than modulation is better better immunity to pam disadvantage is modulation pfm advantage pulse frequency modulation of pulse frequency interference than pam frequency modulation is to noise interference more complex transmitter is better immunity advantage of pulse is more complex 4 pulse frequency immunity to noise
15 frequency modulation pfm pulse frequency modulation 5 pulse frequency
16 of a pulse on represents binary one bit of binary 1 absence transmitter off represents off represents binary 0 each value pulse transmitter on of 0 or absence of a of the pulse 1 is one coded modulationpcm presence transmitter on represents a pulse transmitter each value of or 1 is 6 pulse coded bit of information the pulse transmitter represents binary 1 represents binary 0 pulse coded modulationpcm is one bit pulse transmitter off presence of the 0 or 1 modulationpcm presence of value of 0 binary 0 each 1 absence of
17 analog information such pulses transmit information analog to digital coded modulationpcm binary coding can be to digital ad consisting of many types of analog words of information audio signal by signal by means to represent all binary coding can modulationpcm binary pulses as an audio transmit information consisting information binary coding 7 pulse coded of analog information information such as means of analog information consisting of of many words be used to by means of many words of pulse coded modulationpcm represent all types digital ad converters binary pulses transmit all types of an audio signal can be used used to represent of analog to of information binary such as an
18 8 pulse coded pulse coded modulationpcm
19 9 pulse coded pulse coded modulationpcm
20 0 no transcript
21 deviation frequency swing 1 recapitulation frequency recapitulation frequency modulation modulation centre frequency frequency frequency deviation frequency deviation frequency frequency modulation centre centre frequency frequency
22 2 no transcript
23 modulation what is what is frequency frequency modulation what is centre frequency is frequency swing what is frequency centre frequency what what is centre 3 what is frequency what is is frequency modulation
24 4 pulse modulation
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