The DX2040 and Envoy receivers are TRUE diversity.  Some competitors claim their products are diversity, although we feel that is ‘misleading’.  A true diversity receiver has two complete receivers each with separate aerial ports.  At the end of each receiver chain is a solid state switch which selects the best performing  receiver and routes that audio to the output socket.  This is true diversity reception and it outperforms non-diversity systems hands-down

 The diversity of inputs may be achieved through space, frequency or polarity diversity.  

Simply adding a second aerial socket to a receiver is not diversity.  Some manufacturers use an inferior design where they have just one receiver and two aerials.  They alternate between aerials whenever the signal drops quickly, or below a critical level.  The problem is that the receiver does not know whether the signal on the alternate aerial is better, or worse, than the aerial currently in use.  If the aerial switching results in a poorer signal, the switch will revert back to the former aerial, but not before the lesser signal has been forwarded to the output.  In a true diversity system, both receivers are constantly monitored and the best of those signals is chosen for the output audio.

Even when both receivers have strong input signals, the switching takes place, silently and regularly, on the precept that the stronger signal will be the one least likely to fail.  It is impossible for the switching to choose an inferior signal as this technique is intelligent and knows beforehand what the choice is. 

This protocol is known as 'voting' and is simultaneously conducted at three comparison points within each receiver.

The true diversity receiver has another 'undocumented' feature.  In the unlikely event of a receiver failure, the system will simply lock onto the remaining receiver and continue to function.  This advantage does not exist when you have just one receiver to play with.

 In lesser designs, 'blind' aerial switching takes place at the input of the single receiver.  This may be evident as a low-level click audible on quiet passages.  What is not obvious is that aerial switches are also lossy. i.e you need more input signal to achieve a clean signal.  This means doubling the TX power to compensate.  Additionally, the lack of diversity function will require another doubling of power to achieve comparable range to true diversity. 

Read my article on unlawful power titled Like a Lawsuit with your Wireless Mikes?

  © 2009 Microphone Magic