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--------- The
description of demodulation and modulation channels
Fully digital technology of modulation and demodulation
- High speed conversion of A/D and D/A
- Mean-square waveform
- Gradually over sampling
- Digitally filtering
- High precision DCO
- Adaptive equalization
- Digital bad checksum and error correction
- Complex programmable logic device
- Offset quardri-phase shift keying
Characteristic of fully digital modulation and demodulation channels
- Short delay
- Linear phase
- Flat in band, jitter in band is than 0.01 dB
- Defence degree is nice, which is 80dB outside 2B
- Wide range captured by pilot
- High precision of frequency stability
- High image rejection capability
- High rejection capability of harmonic and intermodulation signal
- Nice interface rejection capability
Technique indexes
- Flat in band, the value of jitter peak is than 0.01 dB
- Interface with adjacent frequency is than –20dB
- SNR in-band is more than 73 dB
- Harmonic rejection outside band is more than 69dB
- Image rejection is more than 76 dB
- Nearly no shift in band
- High DCO distinguish ratio
- High defence degree
- Embedded digital equalizer implements delay distortion
- Modifying line frequency present
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