Keysight E8663D, Руководство пользователя

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Keysight E8357D/67D & E8663D PSG User’s Guide 199
Custom Arb Waveform Generator
Working with Symbol Rates
Working with Symbol Rates
The Symbol Rate menu enables you to set the rate at which I/Q symbols are
fed to the I/Q modulator. The default transmission symbol rate can also be
restored in this menu.
— Symbol Rate (displayed as
Sym Rate
) is the number of symbols per second
that are transmitted using the modulation (displayed as
Mod Type
) along
with the filter and filter alpha (displayed as
Filter
). Symbol rate directly
influences the occupied signal bandwidth.
Symbol Rate is the Bit Rate divided by the number of bits that can be
transmitted with each symbol; this is also known as the Baud Rate.
— Bit Rate is the frequency of the system bit stream. The internal baseband
generator (Option 602) automatically streams the selected Data Pattern at
the appropriate rate to accommodate the symbol rate setting (Bit Rate =
Symbols/s x Number of Bits/Symbol).
— Occupied Signal Bandwidth = Symbol Rate x (1 + Filter Alpha); therefore,
the occupied signal bandwidth is dependent on the filter alpha of the
Nyquist or Root Nyquist filter being used. (To change the filter alpha, refer
to the procedure, “Adjusting the Filter Alpha of a Predefined Root Nyquist
or Nyquist Filter” on page 192 .)
To Set a Symbol Rate
1. Press Preset .
2. Press Mode > Custom > ARB Waveform Generator > Digital Mod Define >
Symbol Rate
or
Mode > Custom > Real Time I/Q Baseband > Symbol Rate
3. Enter a new symbol rate and press Msps , ksps , or sps .