Split sound is an old system in analog television transmitter

Television transmitter

A television transmitter is a device which broadcasts an electromagnetic signal to the television receivers. Television transmitters may be analog or digital.- Types of transmitters :There are many types of transmitters depending on* The system standard...

s. It has long been superseded, but transmitters working on this principle are still in use. In this system there are two almost independent transmitters, one for sound (aural) and one for picture (visual). The system requires more energy input relative to broadcast energy than the alternative system known as intercarrier system

Intercarrier method

The intercarrier method is a system in television that reduces the cost of transmitters and receiver sets by processing audio and video signals together and minimizing the number of separate stages for audio and video signals....

.

Main stages of a transmitter

All superheterodyne transmitter

Superheterodyne transmitter

Superheterodyne transmitter is a radio or TV transmitter which uses an intermediate frequency signal in addition to radio frequency signal.- Types of transmitters :...

s have the following stages:

• Oscillators
• Input stages :Buffer amplifier
  Buffer amplifier
  A buffer amplifier is one that provides electrical impedance transformation from one circuit to another...
  
  s, correction circuits etc.
• IF
  Intermediate frequency
  In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called...
  
   modulator
  Modulation
  In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...
  
   and IF amplifiers
• Frequency mixer
  Frequency mixer
  In electronics a mixer or frequency mixer is a nonlinear electrical circuit that creates new frequencies from two signals applied to it. In its most common application, two signals at frequencies f1 and f2 are applied to a mixer, and it produces new signals at the sum f1 + f2 and difference f1 -...
  
  
• RF power amplifier
  Rf power amplifier
  An RF power amplifier is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power, typically for driving the antenna of a transmitter...
  
  s
• Antenna system
  Antenna (radio)
  An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
  
  

Split sound TV transmitter

In split sound TV broadcasting, two of each of the above stages (except the antenna system) are required, one for sound and one for picture. At the output of the RF amplifiers both signals are combined by a high-power diplexer

Diplexer

A diplexer is a passive device that implements frequency domain multiplexing. Two ports are multiplexed onto a third port . The signals on ports L and H occupy disjoint frequency bands...

; the combined signal is transmitted.

Split sound vs intercarrier system

• In split sound system a high power diplexer is used at the output of the RF amplifiers. Such diplexers are expensive and bulky. In intercarrier system where the combining is achieved at a low level stage no diplexer is used.
• Whereas in intercarrier system RF amplifiers are common for both the visual and aural signals, in split sound system visual and aural transmitters have separate RF amplifiers. Thus, all else being equal, the power consumption of the split sound system is more than that of the intercarrier system.
• In intercarrier system the two IF signals may interfere with each other to produce interference
  Interference (communication)
  In communications and electronics, especially in telecommunications, interference is anything which alters, modifies, or disrupts a signal as it travels along a channel between a source and a receiver. The term typically refers to the addition of unwanted signals to a useful signal...
  
   products out of the operating channel. In order to protect the neighbouring channels a notch filter is used. In split sound no interference products appear at the output, so no filter is needed.