Question

Advantage and disadvantage of superheterodyne receiver

Answer 1

Superheterodyne receivers have essentially replaced all previous receiver designs. The development of modern semiconductor electronics negated the advantages of designs (such as the regenerative receiver) that used fewer vacuum tubes. The superheterodyne receiver offers superior sensitivity, frequency stability and selectivity. Compared with the tuned radio frequency receiver (TRF) design, superhets offer better stability because a tuneable oscillator is more easily realized than a tuneable amplifier. Operating at a lower frequency, IF filters can give narrower passbands at the same Q factor than an equivalent RF filter. A fixed IF also allows the use of a crystal filter[10] or similar technologies that cannot be tuned. Regenerative and super-regenerative receivers offered a high sensitivity, but often suffer from stability problems making them difficult to operate.

Although the advantages of the superhet design are overwhelming, we note a few drawbacks that need to be tackled in practice.

Answer 2

The advantage of the superheterodyne receiver is superior sensitivity and the main disadvantage is the problem of image frequency.

Explanation:

• A superheterodyne receiver can be described as a type of radio receiver in which frequency mixing is used to convert a signal which is received to a fixed intermediate frequency (IF).
• A fixed IF can be processed more conveniently than the original carrier frequency.
• All the previous receiver designs are replaced by superheterodyne receivers.

   The advantages of the superheterodyne receiver are:

• It offers superior sensitivity.
• It provides frequency stability and selectivity due to a tuned oscillator rather than a tuned amplifier.
• As all the processes take place at low frequency, the devices are cheaper.
• Filtering of IF signal is easier than RF signal
• It prevents image noise foldover because of using two IF frequencies before conversion.

  The disadvantages of the superheterodyne receiver are:

• It has the problem of image frequency.
• Additional RF Mixers and LOs (Local Oscillators) are required to convert the signal from RF to IF before conversion to baseband. Due to this, the cost of the overall receiver increases.
• Moreover, for the removal of any LO leakage and undesired frequency, filters are also required for the prevention of image frequencies.
• Due to this, the cost and the complexity of the receiver increase.

#SPJ2