Amplitude Modulation and Demodulation

1. 1CODEC TRANSMITTER
   1. [blank_start]ADC[blank_end] - [blank_start]sampler[blank_end] , [blank_start]quantiser[blank_end] , [blank_start]coder[blank_end]
   2. [blank_start]Source[blank_end] [blank_start]coding[blank_end] - take [blank_start]binary[blank_end] signal and removes [blank_start]redundant[blank_end] bits
   3. [blank_start]Encryption[blank_end] - ensures only user with the [blank_start]correct[blank_end] [blank_start]key[blank_end] can access
   4. [blank_start]Error[blank_end] [blank_start]control[blank_end] [blank_start]coder[blank_end] - encodes signal by [blank_start]adding[blank_end] [blank_start]redundant[blank_end] bits, lengthening the binary signal therefore errors can be [blank_start]corrected[blank_end] at the [blank_start]receiver[blank_end]
   

   1. Asampler
   2. BADC
   3. Cquantiser
   4. Dcoder
   5. ESource
   6. Fcoding
   7. Gbinary
   8. Hredundant
   9. IEncryption
   10. Jcorrect
   11. Kkey
   12. LError
   13. Mcontrol
   14. Ncoder
   15. Oadding
   16. Predundant
   17. Qcorrected
   18. Rreceiver
2. 2MODEM TRANSMITTER
   From CODEC to MODEM [blank_start]multiplexing[blank_end] takes place
   1. [blank_start]Line[blank_end] [blank_start]coding[blank_end] - maps [blank_start]binary[blank_end] stream to a sequence of [blank_start]voltage[blank_end] levels so information has [blank_start]electrical[blank_end] representation
   2. [blank_start]Modulator[blank_end] - converts [blank_start]binary[blank_end] stream to a form that can be [blank_start]transmitted[blank_end], usually [blank_start]band[blank_end] [blank_start]pass[blank_end] [blank_start]waveform[blank_end]

   1. Amultiplexing
   2. BLine
   3. Ccoding
   4. Dbinary
   5. Evoltage
   6. Felectrical
   7. GModulator
   8. Hbinary
   9. Itransmitted
   10. Jband
   11. Kpass
   12. Lwaveform
3. 3MODEM RECIEVER
   1. [blank_start]Demodulator[blank_end] - coverts received [blank_start]band[blank_end] [blank_start]pass[blank_end] [blank_start]waveform[blank_end] to a [blank_start]baseband[blank_end] [blank_start]signal[blank_end]
   2. [blank_start]Detector[blank_end] - converts [blank_start]baseband[blank_end] [blank_start]signal[blank_end] to [blank_start]binary[blank_end] stream
   [blank_start]Demultiplexing[blank_end] occurs between the MODEM and CODEC

   1. ADemodulator
   2. Bband
   3. Cpass
   4. Dwaveform
   5. Ebaseband
   6. Fsignal
   7. GDetector
   8. Hbaseband
   9. Isignal
   10. Jbinary
   11. KDemultiplexing
4. 4CODEC RECIEVER
   1. [blank_start]Error[blank_end] [blank_start]control[blank_end] [blank_start]decoding[blank_end]
   2. [blank_start]Decryption[blank_end]
   3. [blank_start]Source[blank_end] [blank_start]decoder[blank_end]
   4. [blank_start]DAC[blank_end] - [blank_start]PCM[blank_end] [blank_start]decoder[blank_end], [blank_start]reconstruction[blank_end]

   1. AError
   2. Bcontrol
   3. Cdecoding
   4. DDecryption
   5. ESource
   6. Fdecoder
   7. GDAC
   8. HPCM
   9. Idecoder
   10. Jreconstruction
5. 5Need of modulation
   1. to increase [blank_start]operating[blank_end] [blank_start]range[blank_end] the signal energy must be increased, therefore a greater [blank_start]frequency[blank_end] is needed as [blank_start]E=hf[blank_end]
   2. [blank_start]antenna[blank_end] [blank_start]length[blank_end] is proportional to wavelength of the signal
   3. [blank_start]wireless[blank_end] [blank_start]communication[blank_end] can only be done with a modulated singal

   1. Aoperating
   2. Brange
   3. Cfrequency
   4. DE=hf
   5. Eantenna
   6. Flength
   7. Gwireless
   8. Hcommunication
6. 6Amplitude Modulation
   vs(t) = (Vdc + (1) [blank_start]Vm.cos(2*pi*fm*t)[blank_end]) * (2)[blank_start]cos(2*pi*fc*t)[blank_end]
   [blank_start]Message[blank_end] signal = (1)
   [blank_start]Carrier[blank_end] signal = (2)
   The carrier signal is [blank_start]high[blank_end] frequency
   Modulation depth, m =[blank_start]Vm[blank_end]/[blank_start]Vdc[blank_end] = [blank_start]Vmax[blank_end] - [blank_start]Vmin[blank_end]/[blank_start]Vmax[blank_end] + [blank_start]Vmin[blank_end]
   m<1 [blank_start]DSB-AM[blank_end]
   m=1 [blank_start]DSB-AM[blank_end]
   m>1 [blank_start]DSB-DimC[blank_end]
   m=infinite [blank_start]DSB-SC[blank_end]

   1. AVm.cos(2*pi*fm*t)
   2. Bcos(2*pi*fc*t)
   3. CMessage
   4. DCarrier
   5. Ehigh
   6. FVm
   7. GVdc
   8. HVmax
   9. IVmin
   10. JVmax
   11. KVmin
   12. LDSB-AM
   13. MDSB-AM
   14. NDSB-DimC
   15. ODSB-SC
7. 7Power
   P = [blank_start](V/sqrt(2))^2[blank_end]
   Plsb and Pusb = [blank_start]((Vm)^2)/8[blank_end]
   Psb = Plsc + Pusb = [blank_start]((Vm)^2)/4[blank_end]
   Pc = [blank_start]((Vdc)^2)/2[blank_end]
   Ptotal = [blank_start]Pc[blank_end] + [blank_start]Psb[blank_end]

   1. A(V/sqrt(2))^2
   2. B((Vm)^2)/8
   3. C((Vm)^2)/4
   4. D((Vdc)^2)/2
   5. EPc
   6. FPsb
8. 8Amplitude Demodulation
   Envelope/non-coherent/diode detection:
   RsC<<[blank_start]1/fc[blank_end]
   1/fc<<[blank_start]RlC[blank_end]<<1/fm
   AM input must have m[blank_start]>1[blank_end]
   For large signal inputs, forward bias [blank_start]on[blank_end], reverse bias [blank_start]off[blank_end] and the circuit acts as a [blank_start]half[blank_end] [blank_start]wave[blank_end] [blank_start]rectifier[blank_end]
   [blank_start]RC[blank_end] part acts as smoothing circuit
   Output is [blank_start]m(t)[blank_end] + [blank_start]distortion[blank_end]

   1. A1/fc
   2. BRlC
   3. C>1
   4. Doff
   5. Eon
   6. Fhalf
   7. Gwave
   8. Hrectifier
   9. IRC
   10. Jdistortion
   11. Km(t)
9. 9Synchronous/ coherent demodulation:
   More [blank_start]complex[blank_end] and [blank_start]expensive[blank_end] than envelop detection
   Am input -> [blank_start]local[blank_end] [blank_start]oscillator[blank_end] -> v(x) -> [blank_start]low[blank_end] [blank_start]pass[blank_end] [blank_start]filter[blank_end] -> m(t)
   LO must be at the same [blank_start]frequency[blank_end] and in [blank_start]phase[blank_end] with the input signal therefore LO = [blank_start]cos(2*pi*fc*t)[blank_end]
   v(x) = [blank_start]AM input[blank_end] * [blank_start]LO[blank_end]
   Low pass filter ensure only [blank_start](Vdc+m(t))/2[blank_end] gets through
   

   1. Acomplex
   2. Bexpensive
   3. Coscillator
   4. Dlow
   5. Epass
   6. Ffrequency
   7. Gphase
   8. Hcos(2*pi*fc*t)
   9. IAM input
   10. JLO
   11. K(Vdc+m(t))/2
   12. Llocal
   13. Mfilter

Descripción

(Amplitude Modulation and Demodulation) Signals and Communications 1 Test sobre Amplitude Modulation and Demodulation, creado por Rebecca Perriment el 22/05/2018.

Autor

Rebecca Perriment

Idioma

English

Visitas

3

Etiquetas

signals and communications 1amplitude modulation and demodulation

Valoración

Aún sin valoraciones

Valora este test

Valora este test

Más sobre Analog and Digital Modulation