This transmitter's instantaneous available DC power from batteries is 5W, the required transmit power is 28 dBm and the peak-to-average-power ratio is 4 dB. This design must
cover all components starting from the DAC up until the antenna port.
Dear Ekta,
welcome,
The first step in the design is to decide on the configuration. Is a direct conversion radio system or heterodyne? If it is heterodyne with IF digital or analog. What is the value of IF, normally IF at such carrier frequency is 60-80 MHz.
Normally radios for wireless sensor networks are made as simple as possible with the least number of stages. Therefore, they are direct conversion receivers.
consisting of three stages: the baseband processing stage normally FSK modulation, then a data converters D/A to D/A converters and then the rf front end with mixer, amplifiers , filters and matching circuits then the antenna.
Then you can choose the one chip configurable transceiver which matches your requirement from the off the shelf components. You can add low noise amplifiers to the receiver and the an rf power amplifier for the transmitter. You have to add a controlling microprocessor to operate your transceiver under its control.
Best wishes
Dear Ekta,
welcome,
The first step in the design is to decide on the configuration. Is a direct conversion radio system or heterodyne? If it is heterodyne with IF digital or analog. What is the value of IF, normally IF at such carrier frequency is 60-80 MHz.
Normally radios for wireless sensor networks are made as simple as possible with the least number of stages. Therefore, they are direct conversion receivers.
consisting of three stages: the baseband processing stage normally FSK modulation, then a data converters D/A to D/A converters and then the rf front end with mixer, amplifiers , filters and matching circuits then the antenna.
Then you can choose the one chip configurable transceiver which matches your requirement from the off the shelf components. You can add low noise amplifiers to the receiver and the an rf power amplifier for the transmitter. You have to add a controlling microprocessor to operate your transceiver under its control.
Best wishes
Please read my books
1- Communication Engineering Laboratories in Universities of England (part one)
2- Communication Engineering Laboratories in Universities of England (part 2)
You will find them a lot of help to this question.
We need to employ message signal source, carrier signal source, digital modulation module, RF amplifier, antenna. This completes the transmitter.
Abdelhalim Zekry Thank you for your answer. I have never used DAC before, how should I choose DAC for this specific application? DAC will be at the input side of the transmitter followed by amplifier which will be IF signal for the transmitter. Is it right?
Thank you,
Ekta
Dear Ekta,
welcome again!
The digital to analog converter is characterized by a number of bits n for every sample which is called the resolution of data converter. This parameter is determined by the required dynamic range DR= Vmax/ Vmin, where Vmin is the minimum encodable voltage and it is equal to the step size of the coverter and Vmax is the maximum encodable voltage = Vmin 2^n.
So the digital signal is coming in samples with specific number of n. Normally n is about 12: 14 bits.
The other important parameter is the conversion speed in samples per seconds, where the conversion process takes time called the conversion time Tconv and the speed of conversion= 1/Tconv in samples per seconds.
According to Nyquest base band sampling rate fs= the sampling frequency=> 2fmax, with fmax is the maximum frequency in the base band signal. For 1 MHz , the sampling frequency must be greater equal than 2Mhz.
Ekta!
The first stage after the D/A converter is the up mixer and after the up mixer comes the rf driver and after the driver comes the rf power amplifier. then the matching circuit to the antenna.
For the specifications of the communications A/D and D/A converters please see the link: https://www.researchgate.net/post/What_are_the_performance_parameters_of_the_most_advanced_data_converters
I am ready to answer any other question concerning this topic
Best wishes
Hi Ekta,
What you require is a complete radio transmission chain (digital data, digital modulator, mixer/upconverter, DAC and finally the RF Amplifier.
Kindly note that if you have not used DAC before, you should learn using the low frequency DACs and thoroughly understand its functioning.
On the other hand, the DAC that you will use in your final solution will be different altogether in many aspects.
There are many high speed and ultra-high-speed DACs called RF DACs with update rates in several 100MSPS to may be reaching GSPS (?).
But all this comes with a specialized design expertise.
It may not be all in hardware solution but certain software based data processing is unavoidably involved at such fast data rates to modulate and mix both data and RF carrier in digital domain!
If you want to start with simple DAC, may I request to have a look at the article that I have already uploaded on RG and you can download it.
Please feel free if you need any further help.
Wishing you success in your research work!
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