which is an output from a first combinational logic block the d signal is latched in response to a first system clock clk signal the master latch 200 is also coupled to receive a scan in si signal which is strobed in response to a scan a clock sca clk signal the output q1 signal is the complement of the latched d or si signal a slave latch 210 is coupled to latch the q1 signal in response to a second system clock clk signal the slave latch 210 generates a latched signal q that is the complement of the latched q1 signal the q signal is coupled to an signal of a second combinational block since the d and si signals are complemented by the master latch 200 and then complemented by the slave latch 210 the resulting signal is the d or si signal and not their complement a scan slave latch 220 is coupled to latch the q1 signal in response to a scan b clock scb clk the scan slave latch 220 drives the latched data to generate a scan out so signal the d signal that is latched by the master latch 200 and then by.