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The 1st annual Radio Innovative Product Award Winner 2004
Introduced in 2004, the Radio magazine Innovative Product Awards were developed to honor excellence in new product development in the radio industry. The awards demonstrate the talent and commitment of the people in every aspect of development at each company, from concept through sales. The entrants were listed in the 2005 Radio magazine Buyers Guide that was included in the December 2004 issue.
Manufacturers submitted products in several categories, and the winners were selected through an online form by you, the Radio magazine reader. The results were tallied at the end of February, and the winners were presented with their awards at NAB2005. Over the next few months, we will profile each of these winning products.
The 2005 Innovative Product Award entries will be listed in the Radio magazine 2006 Buyers Guide, which will be released in December.
Broadcast Electronics 4MX 50
This 50kW transmitter is based on a patent-pending modulation design and is about half the size of models of comparable power levels. The transmitter is IBOC and DRM compatible. The PA modules can be accessed from the front of the transmitter, while lift-off rear panels provide access to power supplies and all ac connections. The 32 power amp modules each have their own power supply. The power level can be adjusted from 250W to 55kW.
The 4M Modulation used in the transmitter is a modulation design incorporating zero-voltage switching and modulated RF duty cycle providing a typical efficiency of 88 percent. There are other differences between the 4MX design and traditional designs.
In 4M Modulation, the amplitude of the filtered output carrier is determined by calculating the coefficient of the first term of the Fourier expansion of the waveform presented to the combiner transformer. This is different from the waveform produced by filtering a PWM signal, where the amplitude of the filtered-output carrier is a linear function.
In a PWM transmitter, the modulator uses a duty-cycle modulated waveform to create a dc voltage proportional to the audio input signal. This audio-modulated dc is then sent to the PA to product the final AM signal. In a digital transmitter, each PA is turned on and off to produce amplitude modulation. Many PAs are required for modulation. In a 4MX transmitter, the duty cycle of the RF waveform is modulated directly, without the use of a modulator and only requires one PA to produce modulation.
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