> For the complete documentation index, see [llms.txt](https://sathyabama-aic.cognibot.ml/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sathyabama-aic.cognibot.ml/pll-as-frequency-multiplier.md).

# PLL as Frequency Multiplier

Experiment 8

### Aim:

To construct the circuit of PLL as frequency multiplier using IC 567.

### Apparatus Required:

![](https://1636958458-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MdvJMXhfQi-tghqKyC1%2F-MeacqU8E189TnyOLh4_%2F-MeacuDBD27D4ApARY14%2F1.PNG?alt=media\&token=84267b37-ec9b-43aa-9dea-9908fc977c6a)

## Theory:

Here the frequency divider is inserted between the VCO and the phase comparator. Since the output of driver is lock to the input frequency fin, the VCO is actually running at a multiple of the input frequency. The desired amount of multiplication can be obtained by selecting a proper divide by N network. For example to obtain the output frequency f out = 5 fin a divide by 5 network is needed. A small capacitor typically 1000pf is connected between pins 7&8 to eliminate possible oscillations.

### **Circuit Diagram**

![](https://1636958458-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MdvJMXhfQi-tghqKyC1%2F-Meacw7iKqtB-nIMGNX9%2F-Mead1_sncTK8MV9zglu%2F2.PNG?alt=media\&token=25d7edeb-3025-4d00-86aa-c7e65bda38f4)

![](https://1636958458-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MdvJMXhfQi-tghqKyC1%2F-Mead49tybncF9qbDChL%2F-Mead5Ohir4JIc4v4RHL%2F3.PNG?alt=media\&token=a5be40bf-1743-40b3-b8af-f23111d0f98e)

## Internal Block Diagram of  IC-567

![](https://1636958458-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MdvJMXhfQi-tghqKyC1%2F-Mead49tybncF9qbDChL%2F-MeadHdGIQYLz4vPTASl%2F4.PNG?alt=media\&token=daf15359-f338-4980-af83-a6b71e66dfb7)

### **Observations**

![](https://1636958458-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MdvJMXhfQi-tghqKyC1%2F-MeadJMfHW3iewcNLp3n%2F-MeadL7x08eH3lCn1Vvy%2F5.PNG?alt=media\&token=ca25f9a5-0e67-4d53-a130-e06e749d7777)

### Procedure

1. Connections are made as per the circuit diagram.
2. Supply is given and the input is given through audio oscillator. Multiplied output frequency is measured

### Link to experiment

[Go here](http://136.233.21.42:9012/guacamole/) and select Experiment 8

## Demonstration Video

{% embed url="<https://youtu.be/_DznItiQzbY>" %}