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