COE 405
HW#3 Solution

Q.1.   ( 4.2 ) 

		T(0)	T(2)	T(4)	T(5)	
A	Value	‘0’	‘1’	‘1’	‘1’	
	Transaction(s)	(‘1’, 2 ns)	---	---	---	
B	Value	‘0’	‘0’	‘0’	‘0’	
	Transaction(s)	(‘1’, 3 ns)	(‘1’, 1 ns)
(‘0’, 3 ns)	(‘0’, 1 ns)	---	
C	Value	‘0’	‘0’	‘1’	‘1’	
	Transaction(s)	(‘1’, 4 ns)	(‘1’, 2 ns)	---	---	

Q.2.   ( 4.6 ) 

	T(0)	T(0+δ)	T(0+2δ)	T(8)	T(10)	T(20)	T(25)	
W	‘0’	‘0’	‘0’	‘1’	‘1’	‘0’	‘0’	
	(‘1’,8)
(‘1’,10)	(‘1’, 8)
(‘1’,10)	(‘1’, 8)
(‘1’,10)	(‘1’,2)	---	---	---	
X	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	
	---	---	---	---	---	---	---	
Y	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	‘1’	
	---
	---	---	---	---	(‘1’,5)	---	
Z	‘1’	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	‘Z’	
	(‘Z’,δ)	---	---	---	---	---	---	
A	‘0’	‘0’	‘0’	‘0’	‘0’	‘1’	‘1’	
	(‘0’,δ)
(‘1’,20)	(‘1’,20)	(‘1’,20)	(‘1’,12)	(‘1’,10)	---	---	
B	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	
	(‘0’,δ)
(‘1’,40)	(‘1’,40)	(‘1’,40)	(‘1’,32)	(‘1’,30)	(‘1’,20)	(‘1’,15)	

	T(40)	T(40+δ)	T(40+2δ)	T(48)	T(52)	T(55)	
W	‘0’	‘0’	‘0’	‘Z’	‘Z’	‘Z’	
	(‘1’,10)
(‘0’,13)
 (‘Z’,8)	(‘Z’,8)	(‘Z’,8)	---	---	---	
X	‘Z’	‘1’	‘1’	‘1’	‘1’	‘1’	
	(‘1’, δ)	---	---	---	---	---	
Y	‘1’	‘1’	‘1’	‘1’	‘0’	‘Z’	
	(‘0’,12)
(‘Z’,15)	(‘0’,12)
(‘Z’,15)	(‘0’,12)
(‘Z’,15)	(‘0’,4)
(‘Z’,7)	(‘Z’,3)	---	
Z	‘Z’	‘Z’	‘1’	‘1’	‘1’	‘1’	
	---	(‘1’, δ)	---	---	---	---	
A	‘1’	‘1’	‘1’	‘1’	‘1’	‘1’	
	---	---	---	---	---	---	
B	‘1’	‘1’	‘1’	‘1’	‘1’	‘1’	
	---	---	---	---	---	---	

Q.3.   ( 4.14 ) 

	T(0)	T(0+δ)	T(10)	T(14)	T(15)	T(20)	T(20+δ)	T(30)	
A	‘0’	‘0’	‘0’	‘0’	‘0’	‘1’	‘1’	‘Z’	
	(‘0’, δ)
(‘1’, 20)
(‘Z’, 30)
(‘1’, 40)
(‘0’, 50)	(‘1’, 20)
(‘Z’, 30)
(‘1’, 40)
(‘0’, 50)	(‘1’, 10)
(‘Z’, 20)
(‘1’, 30)
(‘0’, 40)	(‘1’, 6)
(‘Z’, 16)
(‘1’, 26)
(‘0’, 36)	(‘1’, 5)
(‘Z’, 15)
(‘1’, 25)
(‘0’, 35)	(‘Z’, 10)
(‘1’, 20)
(‘0’, 30)	(‘Z’, 10)
(‘1’, 20)
(‘0’, 30)	 (‘1’, 10)
(‘0’, 20)	
B	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	
	(‘0’, δ) 
(‘0’, 14)	(‘0’, 14)	(‘0’, 4)	---	---	---	(‘1’, 14)	(‘1’, 4)
(‘Z’, 14)	
C	‘0’	‘1’	‘0’	‘0’	‘Z’	‘0’	‘1’	‘1’	
	(‘1’, δ) 
(‘0’, 10)
(‘Z’, 15)
(‘0’, 20)	(‘0’, 10)
(‘Z’, 15)
(‘0’, 20)	(‘Z’, 5)
(‘0’, 10)	(‘Z’, 1)
(‘0’, 6)	(‘0’, 5)	---	(‘1’, 10)
(‘Z’, 15)
(‘0’, 20)	(‘Z’, 5)
(‘0’, 10)
(‘Z’, 10)
(‘Z’, 15)
(‘0’, 20)	

	T(40)	T(40+δ)	T(50)	T(60)	T(64)	T(65)	T(70)	
A	‘1’	‘1’	‘0’	‘0’	‘0’	‘0’	‘0’	
	(‘0’, 10)	(‘0’, 10)	---	---	---	---	---	
B	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	‘0’	
	(‘Z’, 4)	(‘Z’, 4)
(‘1’, 14)	(‘1’, 4)
(‘0’,1 4)	 (‘0’, 4)	 ---	 ---	 ---	
C	‘Z’	‘1’	‘1’	‘0’	‘0’	‘Z’	‘0’	
	(‘Z’, 5)
(‘0’, 10)	(‘Z’, 5)
(‘0’, 10)
(‘1’, 10)
(‘Z’, 15)
(‘0’, 20)	(‘Z’, 5)
(‘0’, 10)
(‘0’, 10)
(‘Z’, 15)
(‘0’, 20)	(‘Z’, 5)
(‘0’, 10)	(‘Z’, 1)
(‘0’, 6)	(‘0’, 5)	---	

Q.4.   

Entity Q4 is
End Q4 ;

Architecture concurrent  of Q4 is
signal x, x1, x2, y : bit;
begin
y <= '0',  '1' after 10 ns, 
 '0' after 20 ns, '1' after 24 ns, '0' after 28 ns, '1' after 40 ns, 
 '0' after 44 ns, '1' after 50 ns, '0' after 70 ns, '1' after 74 ns, 
 '0' after 78 ns, '1' after 90 ns, '0' after 94 ns, '1' after 98ns;
x1 <= transport y after 5 ns;
x2 <= y after 5 ns;
x <= unaffected when x2'active else x1;
end concurrent;