Mell What is digital intermediate frequency?
Digital Intermediate Frequency (DIF) is the key technology in software radio area. The DIF processing module of shortwave base on software radio technology has DIF processing to input signal, then complete Digital signal processing in digital area. In the DIF processing module, A/D and D/A are very important.
How do you determine intermediate frequency?
The selection of an intermediate frequency for a super-heterodyne receiver involves consideration of the signal frequency, the tuning range, the pass-band width, the minimizing of spurious responses, regeneration stability, and frequency stability.
What is the selection criterion for intermediate frequency?
Intermediate frequency (IF) should be carefully chosen as – High IF results in poor selectivity and therefore poor rejection of adjacent channels. – High IF results in problems in tracking of signals in the receivers. – Image frequency rejection becomes poor at low IF or if very high.
What is image frequency and intermediate frequency?
In heterodyne receivers, an image frequency is an undesired input frequency equal to the station frequency plus (or minus) twice the intermediate frequency. For example, an AM broadcast station at 580 kHz is tuned on a receiver with a 455 kHz IF. The local oscillator is tuned to 580 + 455 = 1035 kHz.
What is meant by intermediate frequency?
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune.
What is the difference between if intermediate frequency and RF radio frequency?
RF to IF conversion is achieved using a RF device called Down-converter. Heterodyne and homodyne receiver architectures are used to convert modulated RF signal to IF signal. Superheterodyne uses 10.7MHz as first IF and 470KHz as second IF….RF vs IF.
| Type of application | Intermediate Frequency value |
|---|---|
| Radar | 30MHz |
How do you convert RF to frequency?
Why was 455 kHz chosen as the intermediate frequency?
As for why 455 KHz, it is historical. Someone chose it originally, and then there were millions of radios to build, so the components specialized for 455 KHz had economies of scale and became quite inexpensive.
Can a radio station be tuned to 455 kHz?
A range of frequencies close to 455 kHz will be unobtainable as the beat frequency of the oscillator would have to be impossibly low. So, tuning in a radio station involves changing this oscillator frequency to a frequency 455 kHz away from the frequency of that sought after radio station. The above section is called the “frequency changer.”
Why does the value of if for the AM receiver is 455 kHz?
For IF=455 kHz this leads to Fim=1510 kHz. This image frequency is at the upper end of the AM band and can easily suppressed by preselection circuitry. For each higher receive frequency the situation becames even better.
How are intermediate frequencies used in radio receivers?
Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. Conversion to an intermediate frequency is useful for several reasons.