APCO-25 Phase 2 RC Filter (Digital Demod)
A custom RC Radio Configuration: defines the physical channel configuration of cdma2000 (IS-2000) signals. Each RC specifies a set of data rates based on either 9.6 or 14.4 kbps. RC1 is the backwards-compatible mode of cdmaOne for 9.6 kbps voice traffic. It includes 9.6, 4.8, 2.4, 1.2 kbps data rates and operates at Spread Rate 1 (SR1). RC3 is a cdma2000 specific configuration based on 9.6 kbps that also supports 4.8, 2.7, and 1.5 kbps for voice, while supporting data at 19.2, 38.4, 76.8, and 153.6 kbps. RC3 also operates at SR1. For more information see Keysight application note "Performing cdma2000 Measurements Today". filter is included with the 89600 VSA software in the %PROGRAMFILES%\Keysight\89600 Software <ReleaseVersion>\89600 VSA Software\Help\Signals directory named apco_p2_RC_filter.mat.
This filter is intended for use when making APCO-25 Phase2 HDQPSK measurements. Using the existing HDQPSK preset will generate acceptable EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. measurements. However, using this user-defined filter will provide a better indication of how close to ideal the signal is in terms of EVM.
After configuring the HDQPSK measurement, perform the following steps to use the provided filter:
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Recall the file as a trace into a register
- Click
- Browse to %PROGRAMFILES%\Keysight\89600 Software <ReleaseVersion>\89600 VSA Software\Help\Signals and select apco_p2_RC_filter.mat
- Select a register to recall the filter into (like D1)
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Configure Demod Properties to use the custom filter
- Click
- Select in the field
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Select the Data Register the file was recalled into
The EVM will be reduced and the IQ Ref Time trace will now have the characteristic constellation points of the HDQPSK-defined filtering.
See Also
