Студопедия
Случайная страница | ТОМ-1 | ТОМ-2 | ТОМ-3
АрхитектураБиологияГеографияДругоеИностранные языки
ИнформатикаИсторияКультураЛитератураМатематика
МедицинаМеханикаОбразованиеОхрана трудаПедагогика
ПолитикаПравоПрограммированиеПсихологияРелигия
СоциологияСпортСтроительствоФизикаФилософия
ФинансыХимияЭкологияЭкономикаЭлектроника

Text 6. Frequency multiplication

Speaking 10 | Text 1. THE DREAM | Text 2. THE OPEN WINDOW | Text 3. | Text 6 ANA FINDS AN APARTMENT | Text 7 CANOPY OF NATURE | Text 9 A MEMORY | Text 10 BEST MAN TRIED TO KILL US BOTH | Text 1. Сomputers Concern You | Text 2. Solar Light by Night |


Читайте также:
  1. A two-letter sequence. In English and other languages, the relative frequency of various _________ in plaintext can be used in the cryptanalysis of some ciphers.
  2. ADVERBS OF FREQUENCY
  3. Cutoff Frequency (частота среза фильтра)
  4. Derivation of frequency
  5. Frequency
  6. Frequency
  7. Frequency

For VHF transmitters, it is often not possible to operate the oscillator at the final output frequency. In such cases, for reasons including frequency stability, it is better to multiply the frequency of the free running oscillator up to the final, required frequency.

If the output of an amplifier stage is tuned to a multiple of the frequency with which the stage is driven, the stage will give a larger harmonic output than a linear amplifier. In a push-push stage, the output will only contain even harmonics. This is because the currents which would generate the fundamental and the odd harmonics in this circuit (if one valve was removed) are canceled by the second valve. In the diagrams, bias supplies and neutralization measure have been omitted for clarity. In a real system, it is likely that tetrodes would be used, as plate-to-grid capacitance in a tetrode is lower, thereby reducing stage instability.In a push-pull stage, the output will contain only odd harmonics because of the canceling effect.

Frequency tripler A basic design for a frequency tripler (screen grids, bias supplies and other elements are not shown).

 

 



Types of AM modulators

A wide range of different circuits have been used for AM. While it is perfectly possible to create good designs using solid-state electronics, valved (tube) circuits are shown here. In general, valves are able to easily yield RF powers far in excess of what can be achieved using solid state. Most high-power broadcast stations still use valves.

 

 
 
Frequency doubler A basic design for a frequency doubler (screen grids, bias supplies and other elements are not shown).  

 

 


Anode modulation using a transformer.   An example of a series modulated amplitude modulation stage.
     

 


Дата добавления: 2015-08-20; просмотров: 50 | Нарушение авторских прав


<== предыдущая страница | следующая страница ==>
Design issues| Plate AM modulators

mybiblioteka.su - 2015-2024 год. (0.005 сек.)