GC1012A Datasheet, PDF (29/30 Pages) Texas Instruments – DIGITAL TUNER CHIP

GC1012A DIGITAL TUNER
DATA SHEET REV 0.1
5.8 LATENCY THROUGH THE GC1012A
Two latencies are of interest, the latency from a step function in to a step function out (midpoint), and the
latency from a step function until the end of the ÒringingÓ in the step function output (endpoint). These latencies are:
Table 6: Latency
Output Mode Midpoint
Real
Complex
41 + 20D
35 + 10D
Endpoint
41 + 40D
35 + 20D
Values of D
(decimation)
1, 2, 4, 8, 16 and 32
2, 4, 8, 16, 32 and 64
Another latency of interest is the delay from SS input to stable WS. The WS strobe becomes stable and is
low after 9 clocks, before 9 clocks the WS is unknown and may go high at any time. The delay until the first valid
high WS is a function of decimation. For decimate by 2 the delay from SS is 10 clocks, for 4 the delay is 12 clocks,
for 8 the delay is 16 clocks and for decimation ratios of 16, 32 and 64 the delay is 24 clocks. WS is high at clock 24
for all decimations.
GRAYCHIP,INC.
- 24 -
FEBRUARY 18, 1998
This document contains information which may be changed at any time without notice