bandpass signaling
DESCRIPTION
Bandpass Signaling. Low Level AM Modulation. Low Level AM Modulation. High Level AM Modulation. http://www.lbagroup.com/technology/am-antenna-tuning-unit.php. http://www.lbagroup.com/technology/am-antenna-tuning-unit.php. http://www.j-hawkins.com/nss.shtml. - PowerPoint PPT PresentationTRANSCRIPT
Bandpass Signaling
Bandpass Signaling
The bandpass communication signal is obtained by modulating a baseband analog or digital signal. We will use complex envelopes because with them we can represent any type of banppass signal.
Definitions: Baseband, Bandpass, and Modulation
DEFINITION. A baseband waveform has a spectral magnitude that is nonzero for frequencies in the vicinity of the origin (i.e., f = 0) and negligible elsewhere.
DEFINITION. A bandpass waveform has a spectral magnitude that is nonzero for frequencies in some band concentrated about a frequency cff where cf . > 0. The spectral magnitude is negligible elsewhere. cf is called the carrier frequency.
DEFINITION. Modulation is the process of imparting the source information onto a bandpass signal with a carrier frequency cf by the introduction of amplitude or phase perturbations or both. This bandpass signal is called the modulated signal s(t), and the baseband source signal is called the modulating signal m(t).
Bandpass Signaling.
Representation of Modulated Signals
})(Re{)(tcjetgts
)]([)( tmgtg
Spectrum of Bandpass Signals
22 )(21
)( tgtvPv
Spectrum of Bandpass Signals
Bandpass Filtering and Linear Distortion
Bandpass Filtering and Linear Distortion
AM Modulation
Amplitude Modulated Signal
AM Modulation
Spectrum
Peak Envelope Power
AM Modulation
Low Level AM Modulation
Low Level AM Modulation
AM Detection
High Level AM Modulation
http://www.lbagroup.com/technology/am-antenna-tuning-unit.php
http://www.lbagroup.com/technology/am-antenna-tuning-unit.php
http://www.j-hawkins.com/nss.shtml
http://www.j-hawkins.com/nss.shtml
http://mcnally.cc/kyw.htm
http://www.mibuzzboard.com/phpBB3/viewtopic.php?f=12&t=30498&p=377748&sid=5aafd94d90fef4fa32f74fd9b0b79516
Can you use envelope detector in DSB ?
AM Modulation
Double Side Band Suppresed Carrier
ttmAtscc cos)()(
Efficiency
cc
c ffMffMA
fS )(2
)(
DSB Modulation
AM Modulation
PLL
Double Side Band Suppresed Carrier receivers
Single Sideband
ASYMMETRIC SIDEBAND SIGNALS Single SideBand
Bandpass Signaling
SOME FOURIER TRANSFORM PAIRS
Single Sideband
Single Sideband Transmitters
Remember, we are using s(t) =v(t)
Single Sideband Transmitters
Vestigial Sideband
Vestigial Sideband