IPR-CIC Altera, IPR-CIC Datasheet - Page 31

• Manufacturer Part Number: IPR-CIC
• Description: IP CORE Renewal Of IP-CIC
• Manufacturer: Altera

Specifications of IPR-CIC

• Software Application: IP CORE, DSP Filters And Transforms
• Supported Families: Arria GX, Cyclone, HardCopy, Stratix, Stratix II
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Lead Free Status / RoHS Status: na

Chapter 4: Functional Description
FIR Filter Compensation Coefficients
Variable Rate Change Factors for Decimation and Interpolation
Figure 4–8. Variable Rate Change Decimation CIC Filter Timing Diagram
FIR Filter Compensation Coefficients
© December 2010 Altera Corporation
out_ready
out_valid
out_error
in_ready
in_valid
in_error
reset_n
clken
rate
clk
f
1
Data is transferred as packets using Avalon Streaming (Avalon-ST) interfaces. A
general description of these interfaces is given in
page
For an example design using multi-channel MISO and SIMO architectures, refer to
AN442: Tool Flow Design of Digital IF for Wireless
You can optionally set minimum and maximum values for the decimator or
interpolator rate change factors and enable the rate change factors to be set at run
time. When these options are set, an additional rate port is provided that can be used
to specify the rate change factor. For information about how to enable the options for
variable rate change factors, refer to
If variable rate change factors are enabled, the MegaCore function must be reset when
the rate change factor is changed otherwise the previous memory/register values
would be used. The filter mode (interpolation or decimation) cannot be changed at
run time.
Figure 4–8
change decimation CIC filter. Note how the out_valid signal changes its period
according to the variable rate change.
CIC filters have a low-pass filter characteristic. There are only three parameters (the
rate change factor R, the number of stages N, and the differential delay M) that can be
modified to alter the passband characteristics and aliasing/imaging rejection.
However, due to their drooping passband gains and wide transition regions, CIC
filters alone cannot provide the flat passband and narrow transition region filter
performance that is typically required in decimation or interpolation filtering
applications.
4–9.
illustrates the input and output timing relationships for a variable rate
8
8
“Parameter Setting Examples” on page
00
00
Systems.
“Avalon Streaming Interface” on
CIC MegaCore Function User Guide
2
3–1.
4–7