 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
ADV7181BCP Datasheet(PDF) 91 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
ADV7181BCP Datasheet(HTML) 91 Page - Analog Devices |
|
|
91 / 96 page  ADV7181B Rev. 0 | Page 91 of 96 DIGITAL INPUTS The digital inputs on the ADV7181B are designed to work with 3.3 V signals, and are not tolerant of 5 V signals. Extra compo- nents are needed if 5 V logic signals are required to be applied to the decoder. ANTIALIASING FILTERS For inputs from some video sources that are not bandwidth limited, signals outside the video band can alias back into the video band during A/D conversion and appear as noise on the output video. The ADV7181B oversamples the analog inputs by a factor of 4. This 54 MHz sampling frequency reduces the requirement for an input filter; for optimal performance it is recommended that an antialiasing filter be employed. The recommended low cost circuit for implementing this buffer and filter circuit for all analog input signals is shown in Figure 43. The buffer is a simple emitter-follower using a single npn transistor. The antialiasing filter is implemented using passive components. The passive filter is a third-order Butterworth filter with a −3 dB point of 9 MHz. The frequency response of the passive filter is shown in Figure 42. The flat pass band up to 6 MHz is essential. The attenuation of the signal at the output of the filter due to the voltage divider of R24 and R63 is compen- sated for in the ADV7181B part using the automatic gain control. The ac-coupling capacitor at the input to the buffer creates a high-pass filter with the biasing resistors for the transistor. This filter has a cut-off of: {2 × π × (R39||R89) × C93}–1 = 0.62 Hz It is essential that the cutoff of this filter be less than 1 Hz to ensure correct operation of the internal clamps within the part. These clamps ensure that the video stays within the 5 V range of the op amp used. 0 –20 –40 –60 –80 –100 –120 100k 30M 10M 3M 1M 300k 300M 1G 100M FREQUENCY (Hz) Figure 42. Third-Order Butterworth Filter Response |
Similar Part No. - ADV7181BCP |
|
Similar Description - ADV7181BCP |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
