Terrestrial Tx Clock Phase; Terrestrial Rx Clock Phase; Table A-19. Transmit Timing Parameters; Table A-20. Receive Timing Parameters - Comtech EF Data SDM-2020 Installation And Operation Manual

SDM-2020 Satellite Demodulator
Parameter
f
T
t
w
t
su
t
h
The timing parameters for the serial data receive interface are listed in Table A-20.
Parameter
f
T
t
w
t
su
t
h
A.5.4.7

Terrestrial TX Clock Phase

The ECL/HSSI interface supports TX clock phase inversion. Terrestrial data is sampled
on the falling edge of TT clock in normal phase selection. In inverted phase selection, the
terrestrial data will be sampled on the rising edge of TT clock.
A.5.4.8

Terrestrial RX Clock Phase

The ECL/HSSI interface supports RX clock phase inversion. Terrestrial data (RD) is
synchronous to RT. In normal mode, the falling edge of the RT clock will be centered on
the RD signal. In inverted phase selection, the rising edge of RT clock will be centered on
the RD signal.
Rev.3

Table A-19. Transmit Timing Parameters

Description
Operating frequency (1/T)
Clock period (1/f)
Clock pulse width
Setup time, DATA or SYNC to CLOCK
Hold time, CLOCK to DATA or SYNC invalid

Table A-20. Receive Timing Parameters

Description
Operating frequency (1/T)
Clock period (T)
Clock pulse width
Setup time, DATA, DVALID, or SYNC to
CLOCK
Hold time, CLOCK to DATA, DVALID or
SYNC invalid
Data Interfaces
Min Max Units
1.5 100 MHz
10 666 nsec
4 - nsec
3 - nsec
3 - Nsec
Min Max Units
1.5 100 MHz
10 666 nsec
4 - nsec
3 - nsec
3 - nsec
A–37