RF Transmitter Circuits

  

The transmitting system consists of two tuned circuits such that the one containing the spark-gap is a persistent oscillator; the other, containing the aerial structure, is a free radiator maintained in oscillation by being coupled to the first. The transmitting system consists of two electrically coupled circuits, one of which, containing the air-gap, is a powerful but not persistent oscillator, being provided with a device for quenching the spark so soon as it has imparted sufficient energy to the other circuit containing the aerial structure, this second circuit then independently radiating the train of slightly damped waves at its own period.

For a fixed frequency transmitter one commonly used method is to use a resonant quartz crystal in a Crystal oscillator to fix the frequency. Where the frequency has to be variable, several options can be used.
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. The task of many transmitters is to transmit some form of information using a radio signal (carrier wave) which has been modulated to carry the intelligence.
 
A few rare types of transmitter do not carry information: the RF generator in a microwave oven, electrosurgery, and induction heating. RF transmitters that do not carry information are required by law to operate in an ISM band. In many cases the carrier wave is mixed with another electrical signal to impose information upon it. This occurs in Amplitude modulation (AM). Amplitude Modulation: In Amplitude modulation the instantaneous change in the amplitude of the carrier Frequency with respect to the amplitude of the modulating or Base band signal.
 
 

 

 

News

RF Vendors Tackle Repack, Next-Gen Details | TVNewsCheck.com

TV News Check RF Vendors Tackle Repack, Next-Gen Details | TVNewsCheck.com TV News Check The FCC-mandated TV spectrum repack and ATSC 3.0 will be the biggest trends in RF developments at the 2017 NAB Show. However,...

Mar 23, 2017

Sennheiser in RF Control at Brits 2017

EtNow.com Sennheiser in RF Control at Brits 2017 EtNow.com For this RF -heavy environment, Sennheiser's flagship Digital 9000 series microphones were deployed for all presenters. SKM 9000 transmitters with EM...

Mar 24, 2017

GatesAir Optimizes Next-Generation Transmitter Portfolio for Spectrum Repack at 2017 NAB Show

GatesAir Optimizes Next-Generation Transmitter Portfolio for Spectrum Repack at 2017 NAB Show TV Technology The new Maxiva™ ULXTE liquid transmitter joins the recently-announced UAXTE air-cooled transmitter to give...

Mar 16, 2017

Pasternack Debuts Millimeter Wave Transmitter Module Covering ...

Yahoo Finance Pasternack Debuts Millimeter Wave Transmitter Module Covering ... Yahoo Finance New Module Features Integrated Synthesizer and Power Amplifier Generating Output P1dB Up to +12 dBm IRVINE, Calif., March...

Mar 23, 2017

On The NAB Exhibit Floor: DTC

On The NAB Exhibit Floor: DTC TV News Check Domo Broadcast, a subdivision of Domo Tactical Communications will feature its new Broadcast Nano HD transmitter , PRORXD 8-Way Diversity RF wireless receiver platform, and...

Mar 20, 2017

Have an IoT Product? Follow Federal Labeling Requirements.

Lexology (registration) Have an IoT Product? Follow Federal Labeling Requirements. Lexology (registration) Using a modular transmitter does not permit you to avoid testing and labeling requirements that other RF...

Mar 7, 2017

Global Transmitter of RF Evaluation Boards Market 2017 Analog ...

NetDugout Global Transmitter of RF Evaluation Boards Market 2017 Analog ... NetDugout The Global Transmitter of RF Evaluation Boards Market Key Vendors are Analog Devices Inc., Atmel, Adafruit Industries LLC, Freescale...

Mar 8, 2017

MACOM launches 100G CWDM4 transmitter L-PIC chipset for 400G ...

MACOM launches 100G CWDM4 transmitter L-PIC chipset for 400G ... Semiconductor Today MACOM Technology Solutions Inc of Lowell, MA, USA (which makes semiconductors, components and subassemblies for analog RF,...

Mar 22, 2017

The Sennheiser Digital 6000 Microphone System Is Now Shipping

The Sennheiser Digital 6000 Microphone System Is Now Shipping Live Design A new, user-friendly menu control with a bright, white OLED display gives a quick overview of the RF signal, link quality, audio signal, battery...

Mar 2, 2017

Sennheiser Helps Lady Gaga Spread Message Of Unity At Super Bowl

Sennheiser Helps Lady Gaga Spread Message Of Unity At Super Bowl Live Design Navigating as dense a wireless environment as the Super Bowl is no small feat, but the Sennheiser SKM 5200 transmitters and EM 3732-II receivers...

Feb 24, 2017

Units & Modules