Universal counter is a block used to make all the measurements of time period and frequency. The universal counter uses logic gates which are selected and controlled by a single front panel switch known as the function switch. It works in two modes namely

• Frequency Mode

• Period Mode

   

With the function switch in the frequency mode, a control voltage is applied to the specific logic gate circuitry. Hence the input signal is connected to the counted signal channel of the main gate.

The selected output from the time base divider is simultaneously gated to the control flip-flop, which enables or disables the main gate. Both control paths are latched internally to allow them to operate only in proper sequence.

When the function switch is on the period mode, the control voltage is connected to proper gates of the logic circuitry, which connects the timebase signals to the counted signal channel of the main gate. At the same time the logic circuitry connects the input to the gate control for enabling or disabling the main gate. The other function switches, such as time interval ratio and external standards perform similar functions.