Dual Resampler 1Y
Features
- General-purpose interpolator
- Arbitrary (even time-varying and non-integer) input / output sample rate ratios
- Optimized for 10-bit input and output datapath word widths (others on request)
- Designed for maximum speed (fMAX > 140 - 300 MHz, depending on device)
- Optimized for ACEX™ 1K, FLEX® 10KE, APEX™ 20KE, APEX 20KC, and Mercury™ devices
- Ideal for the following applications:
- Digital modulators/demodulators
- Wireless & wired telecommunications systems
Block Diagram
Figure 1 shows the block diagram for the megafunction.
Description
The CommStack Dual Resampler 1Y megafunction resamples a complex digital baseband signal, interpolating it from a lower-rate complex input sequence to a higher-rate complex output sequence.
While many interpolators operate only at fixed integer input-to-output sampling rate ratios 1:N, and more complicated multi-rate (interpolate / decimate) schemes are often used just to obtain fixed integer-fractional ratios M:N, the CommStack Resampler megafunction offers much greater flexibility in a smaller footprint. CommStack's designs support not only fixed integer and fixed integer-fractional ratios, but also arbitrary non-fixed ratios Y, where Y may be time varying. This can be used to adjust output versus input phase continuously, or to change input and/or output sampling rates on-the-fly, even by non-integer ratios.
This function may be used as the final stage of digital modulator designs, or as the stage just prior to an up converter, e.g., in data-over-cable service interface specification (DOCSIS), LMDS, or MMDS applications. The input signal may be in any of a variety of formats, including AM, BPSK, QPSK, GMSK, 8-PSK, OFDM, or 16- to 256-QAM.
The datapath is optimized for 10-bit inputs and outputs, but other datapath word widths may be implemented on a customized basis at nominal cost. Additional precision is implemented internally to maintain 10-bit accuracy in the result.
With performance from 140 Mbps to over 300 Mbps, CommStack's Dual Resampler 1Y megafunction provides a high-speed and flexible interpolator capability well suited to many modern digital signal processing (DSP) applications.
Device Utilization Examples
Table 1 lists the typical device utilization results for the megafunction.
| Table 1: Typical Device Utilization for Megafunction |
| Device |
Speed Grade |
Logic Cells |
EABs (1) |
fMAX (typical) |
EP1K100,
EPF10K100E |
-1 |
828 |
1 |
147 MHz |
| EP20K100E |
-1 |
827 |
1 |
177 MHz |
| EP20K100C |
-7 |
827 |
1 |
210 MHz |
| EP1M120 |
-5 |
828 |
2 |
308 MHz |
Note:
- EABs = Embedded array blocks
Contact Information
For additional information, contact
CommStack, Inc.
72 Fairfax Avenue
Atherton, CA 94027
Phone: (650) 701-0939
E-mail: info@commstack.com
Internet: http://www.commstack.com
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