Hi

Currently at university at the moment in first year and been told as a project I must design a and build a frequency meter.

"you are required to design and build a circuit to display the frequency of a TTL compatible square wave wave. Frequency meters consist of a counter, a display and a gate that is opened and closed under the control of an accurate oscoscillator, plus some control. Your circuit should consist of three seven segment displays and indicate frequency in the range of 0-999hz. Your circuit should freeze the display when the gate closes so that it can be read, and reset it to zero before the gate opens again. It will therefore be necessary to design some gate and reset control circuitry, and possibly latch"

Above is the exact brief given.

I'm unsure where to start at the moment my lecturer has only taught us about gates so far.

So any help being that of youtube videos or websites to read to help me understand to design and build this would be great.

Many thanks
Rhys

 

Welcome to AAC!

my lecturer has only taught us about gates so far.

Then your next step is to google for tutorials on counters and displays.

 

Cheers

Started doing that, but at the moment I'm struggling to understand how they all work togethe, to make a frequency meter.

Will that all become clear once I know enough about them?

 

try to understand something like a zero crossing detector ?

 

try to understand something like a zero crossing detector ?

TTL doesn't cross zero. You're going to be using digital chips to count highs and lows.

Start with a "block diagram". This is the input, it must have at least this much impedance and that much speed. This is the gate. It must open and close...how fast and how accurate? etc.

 

You will need some time control system to open and close the gate (e.g. Exactly one second).

Here is the concept. The real work come in the 3-digit display! Not done here!

 

Gopher laid out a good start. Just begin by looking at the blocks and what the building blocks each do. That drawing is a good illustration, really good.

Ron

 

Cheers for all your help so far,

Looks like I have a lot of theory to learn first before I can start trying to tackle designing this.

 

Start looking at other designs, that will give you a starting point.

http://www.hobbyprojects.com/F/Frequency_Counters.html

 

You have to find the theory of frequency meter and how many functions it needed, and then solve them one by one, and put them together, the last is to test the function and debug.

 

Cheers for all your help so far,

Looks like I have a lot of theory to learn first before I can start trying to tackle designing this.

Not so much. Look at the list of chip available in the 7400 series and then look into what they do. The datasheets are widely available and straightforward to read. If not, make another post on this thread.

http://en.wikipedia.org/wiki/List_of_7400_series_integrated_circuits

 

I also think the block diagram is great.

 

I say gophers are much smarter than groundhogs. The GHs can't even predict the weather yet this gopher can simplify a frequency counter right down to the simple basics.

 

TTL doesn't cross zero. You're going to be using digital chips to count highs and lows.

Start with a "block diagram". This is the input, it must have at least this much impedance and that much speed. This is the gate. It must open and close...how fast and how accurate? etc.

thanks, missed the ttl part.