PDSP16488AMA Mitel Networks Corporation, PDSP16488AMA Datasheet - Page 8

• Manufacturer Part Number: PDSP16488AMA
• Description: Single Chip 2D Convolver with Integral Line Delays
• Manufacturer: Mitel Networks Corporation

PDSP16488A MA
DELAY COMPENSATION FOR LARGE WINDOWS
each of which is implemented in an individual device. If
necessary the partial window must be padded with zero
coefficients to become one of the standard sizes. When
constructing a large window it is necessary to delay the
expansion data inputs in order to compensate for growth in the
horizontal direction. Delays in the partial sums are also
necessary to compensate for the total pipeline delay needed
to produce the previous complete horizontal stripe.
the first, the expansion input must be delayed by the width of
the partial window, before it is added to the internal sum. Since
partial windows can only be 4 or 8 pixels wide,a delay of 4 or
8 pixel clocks is needed. There is, however, an in-built delay
8
A large window is composed of several partial windows
Within each device in a horizontal stripe, apart from
INPUT
delays
delays
4 clock
delays
delays
4 clock
delays
delay
delays
delay
D
0
0
D
4
0
ZERO
delays
delays
line
delays
line
B3 = 0
B3 = 0
B3 = 1
D = 4+S(N-1) Defined by D3:2
line
D3:2 = 00
D = 4+S(N-1) Defined by D3:2
WIDTH = S
WIDTH = S
WIDTH = S
delays
D0 = 0
D0 = 0
delays
delays
D0 = 0
0
0
0
4 clock
4 clock
delay
delay
4 clock
delay
Fig. 6. Multi-Device Delay Paths
of 4 pixels in the inter device connection, and the
PDSP16488A thus only needs an
expansion input by an additional four pixels.
convolvers feeds the expansion input of the first device in the
next row. This is shown in Figure 6. With this arrangement, the
position of the partial window as illustrated, is the inverse of
its vertical position on a normal TV screen. Thus the top, left
hand, device corresponds to the bottom, left hand, portion of
the complete window.
with respect to the original data input by an amount given by
the formula;
a row and S is the partial window width, ie 4 or 8.
DELAY = 4 + [N-1].S where N is the number of devices in
delays
delays
delays
delays
delays
delays
0
D
4
0
The data from the last device in a horizontal row of
The output from the last device in the row is delayed
0
D
delays
delays
delays
line
line
line
B3 = 1
D3:2 = 00
B3 = 0
B3 = 0
D = 4+S(N-1) Defined by D3:2
D = 4+S(N-1) Defined by D3:2
D0 = 0 or 1
D0 = 0 OR 1
WIDTH = S
WIDTH = S
D0 = 0 OR 1
WIDTH = S
delays
delays
delays
0/4
0/4
0/4
N th DEVICE IN THE ROW
N th DEVICE IN THE ROW
N th DEVICE IN THE ROW
0 IF S = 4, 4 IF S = 8
0 IF S = 4,4 IF S = 8
0 IF S = 4, 4 IF S = 8
4 clock
4 clock
delay
delay
4 clock
delay
option
OUTPUT
to delay the