Latch wont latch - Electronic Circuits Projects Diagrams Free

sajubeni · 18th September 2006, 05:27 PM

Hi,
I am desigining a 64-ary QAM. While desiging,i encountered an unexpected problem in the latch.The problem is the latch wont latch.Since this is for study purpose,i am using low frequencies only.I am giving a clock frequency of 6.4KHz and the data rate is 19.2Kbps. Logic 1 is +5 Volt and Logic 0 is 0 Volt. When used under these condition,the latch is not working.I am using DM74LS374 latch.Can anybody please help me out?

Saju.

Hero999 · 18th September 2006, 09:49 PM

Please post a schematic.

Papabravo · 18th September 2006, 10:45 PM

That's funny. Every LS374 I've ever used was transparent when the latch enable signal was high and latched when latch enable was low. That is the only possible misinterpretation I can think of.

jbeng · 18th September 2006, 11:49 PM

Another issue might lie in the fact that the 'LS374 is an octal d-type flip-flop, not an octal latch. The 'LS373 is an octal transparent latch. Both have tri-state outputs. Personally, I like the '573 and '574 for ease of PC board layout.
JB

sajubeni · 8th October 2006, 08:32 AM

Finally, it worked. There was a problem with the clock. I want to know whether is there any IC's available particularly for QAM. If u know,please help me out.

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18th September 2006, 05:27 PM	#1
sajubeni	Latch wont latch Hi, I am desigining a 64-ary QAM. While desiging,i encountered an unexpected problem in the latch.The problem is the latch wont latch.Since this is for study purpose,i am using low frequencies only.I am giving a clock frequency of 6.4KHz and the data rate is 19.2Kbps. Logic 1 is +5 Volt and Logic 0 is 0 Volt. When used under these condition,the latch is not working.I am using DM74LS374 latch.Can anybody please help me out? Saju.

18th September 2006, 09:49 PM	#2
Hero999	Please post a schematic. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

18th September 2006, 10:45 PM	#3
Papabravo	That's funny. Every LS374 I've ever used was transparent when the latch enable signal was high and latched when latch enable was low. That is the only possible misinterpretation I can think of.

18th September 2006, 11:49 PM	#4
jbeng	Another issue might lie in the fact that the 'LS374 is an octal d-type flip-flop, not an octal latch. The 'LS373 is an octal transparent latch. Both have tri-state outputs. Personally, I like the '573 and '574 for ease of PC board layout. JB __________________ Nothing is impossible for the man who doesn't have to do it himself - Weiler's Law

8th October 2006, 08:32 AM	#5
sajubeni	Qam Ic Finally, it worked. There was a problem with the clock. I want to know whether is there any IC's available particularly for QAM. If u know,please help me out.