Ramp Type DVM Block Diagram – Explain | New Topic

In this note, we are going to know about Ramp Type DVM Block Diagram. Also we will know about its working, advantages etc. Welcome to Poly Notes Hub, a leading destination for diploma and degree engineering notes.

Author Name: Arun Paul.

What is Ramp Type DVM?

A Ramp Type DVM is a digital voltmeter that measures voltage by calculating the time it takes for a linear ramp signal to increase (or decrease) from 0V to the input voltage level and converting that time into a corresponding digital value.

Specifications of Ramp Type DVM

• The measurement range typically from millivolts (mV) to kilovolts (kV).
• The resolution depends on clock frequency and counter uses.
• The accuracy is ±0.1% to ±1%.
• It has high input impedance (typically >10MΩ).
• The response time very fast typically from a few milliseconds to seconds.
• The power consumption is also low.

Ramp Type DVM Block Diagram

Here is the block diagram of Ramp Type DVM –

• Test DC Input and Ranging & Attenuator: The voltage to be measured is used as the test DC input. Because input voltages can fluctuate greatly, the Ranging & Attenuator component adjusts the voltage to maintain it within the voltmeter’s functioning range. It ensures that both high and low voltages can be measured without exceeding the device’s specifications.
• Input Comparator: The attenuated input voltage is sent into an Input Comparator, which compares it to the reference ramp voltage produced by the ramp generator. When the ramp voltage exceeds the input voltage level, the comparator sends a Start Pulse, activating the gate circuit.
• Ramp Generator: The Ramp Generator generates a voltage that increases or decreases linearly with time. This ramp voltage serves as a standard to which the input voltage is compared. The precision of time measurements is determined by the pace at which the ramp changes.
• Ground Comparator: The ground (GND) comparator compares the ramp voltage to zero or a predetermined reference level. When the ramp approaches zero, a Stop Pulse is sent to the gate circuit, indicating the end of the measurement interval.
• Oscillator: The Oscillator produces high-frequency clock pulses, which are counted during the time interval when the gate is open. The measurement’s precision is determined by the stability and frequency of the clock pulses.
• Gate Circuit: The Gate Circuit functions as a switch, allowing clock pulses to reach the counter only when it is open. When the input comparator receives a start pulse, the gate opens; when the ground comparator receives a stop pulse, the gate closes.
• Counter: The Counter counts the number of pulses that pass through the gate throughout the time interval. Because the pulse count is proportional to the input voltage, the counter essentially translates the time measurement to a numerical number that represents the voltage.
• Readout Unit: Finally, the Readout Unit shows the measured voltage in digital format, producing a precise and easy-to-read output. This can be displayed using a seven-segment display, LCD, or other digital output devices.

Working of Ramp Type DVM

A Ramp Type Digital Voltmeter (DVM) works by measuring the time it takes for a linear ramp voltage to rise or fall to the input voltage level. The procedure begins with a ramp generator, which produces a voltage that gradually increases or decreases over time. This ramp voltage is then supplied into a comparator, which constantly compares it to the unknown input voltage.

When the ramp voltage equals the input voltage, a gate circuit is activated, allowing clock pulses from a high-frequency clock generator to flow through. These pulses are tallied by a digital counter, which begins monitoring the time length. As the ramp voltage changes, it finally hits zero or a predetermined reference level, at which time the gate circuit closes and the count stops.

The number of pulses detected during this time frame is proportional to the amount of the input voltage. Finally, the counter value is processed and presented digitally, resulting in an exact voltage reading. The precision of the measurement is determined by the clock pulse frequency and the stability of the ramp generator, which ensures great accuracy in voltage measurement.

Advantages of Ramp Type DVM

Here we have listed ramp type DVM advantages –

• This device has high accuracy and resolution
• The operation of this multimeter is very simple.
• The power consumption is very low.
• It is suitable for DC voltage measurement.
• It can be easily interfaced with digital systems

Applications of Ramp Type DVM

Here we have listed ramp type DVM uses –

• Used in laboratories for precise voltage measurements
• Used in industrial automation and control systems
• Used for calibrating of analog and digital circuits
• Used in digital panel meters in electrical and electronic instruments
• Used in test and measurement equipment