Digital modulation and demodulation blocks incur delays between their inputs and outputs that
result in an offset in the arrival time of the received data. Data that enters a modulation or
demodulation block at time T appears in the output at time
T+delay. Take system delays into account when comparing transmitted data
with received data, such as in overlaid plots or when computing error statistics. As shown here,
the OQPSK modulation-demodulation delay varies depending on the pulse shaping filter,
input/output data setting, and simulation configuration.
Pulse Shape | Rate Options | Treat Each Discrete Rate as a Separate Task? | Input/Output Data (*) | End-to-End Delay Incurred by an OQPSK Modulator-Demodulator Block Pair
(in samples) |
---|
Half sine or
Custom | Enforce single-rate
operation | N/A | Integer | 1 |
Bit | 2 |
Allow multirate
processing | false (single tasking) | Integer | length(data) + 1 + 1 |
Bit | length(data) + 2 + 2 |
true (multitasking) | Integer | length(data) + 1 + 2 |
Bit | length(data) + 2 + 4 |
Normal raised cosine or
Root raised cosine | Enforce single-rate
operation | N/A | Integer |
Filter span (in symbols) |
Bit | 2*Filter span (in symbols) |
Allow multirate
processing | false (single tasking) | Integer | length(data) + Filter span (in symbols) +
1 |
Bit | length(data) + 2*Filter span (in symbols) +
2 |
true (multitasking) | Integer | 2*length(data) + Filter span (in symbols) +
2 |
Bit | 2*length(data) + 2*Filter span (in symbols) +
4 |
(*) The data type parameter is
Input type for modulation and Output
type for demodulation. |