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