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The process of multiplting two time domain signals generates signals at sum and difference frequencies (where the IF is the difference frequency). This implies that any signal whose frequency differs from the LO by the same amount that the RF does, will also impose its self on the same IF. E.G. if RF = LO - IF, then the signal at LO + IF will also downconvert and apear at IF. This signal (in this case LO + IF) is called the image frequency IM. and must be attenuated (perhaps by an image rejection filter) prior to mixing.
Where the example above applies to high-side LO injection (LO > RF) the same is true for low-side LO injection (LO < RF).
What else can I help you with?
What is the function of a mixer of an AM receiver?
The mixer in an AM receiver combines the incoming radio frequency (RF) signal with a local oscillator signal to produce an intermediate frequency (IF) signal. This process allows for easier amplification and filtering of the desired audio signal, as the IF is typically at a lower frequency. The mixer effectively translates the high-frequency AM signal down to a more manageable frequency for further processing, enabling clearer audio reception.
Tell you what an intermediate frequency amplifier do?
The intermediate frequency (IF) amplifier lies between the mixer and the demodulator. The mixer shifts the input radio frequency (RF) signal into the range of the IF amplifier. The IF amplifer is a band pass amplifier, so only RF signals that are the IF frequency distance away from the local oscillator in the mixer can pass through to the demodulator. This process is called the superhetrodyne process.
What are the 4 parts to a receiver?
radio frequency amplifier intermediate frequency( If strip) in a superheterodyne radio mixer /demodulator Audio amplifier
When would a mixer in an AM superhet receiver output be zero?
The mixer output should be a signal at the IF frequency ... generally 455 KHz in an AM radio. It's the difference-frequency between the onboard local oscillator and the frequency of whatever's coming down from the antenna. Expect no RF energy from the mixer when there's no RF energy in the passband of the RF amp section ahead of the mixer ... i.e. nothing being received. If the RF section is wide open across the band, or there IS no RF section and the antenna goes straight to the mixer, and there's no mixer output, then this indicates that either you're on the far side of the moon receiving nothing across the whole AM band, or else your antenna input is grounded and the mixer is shielded.
How do you calculate an image frequency?
Let's take an example. Suppose that the intermediate frequency is 10,7 MHz (FM). The local oscillator works on 110,7 MHz. First case: You receive a signal of 100 MHz, the mixer will generate a frequency of 110,7 + 100 = 210,7 MHz, which will be rejected by the band-pass filter. The difference of the two frequencies is 110,7 - 100 = 10,7 MHz (desired one). Second case: You receive a signal of 121,4 MHz. The sum of that frequency and the local oscillator is 232,1 MHz, which will be rejected. The difference is 121,4 - 110,7 = 10,7 MHz. So the image frequency in that case is going to be 121,4 MHz.
Why do DJ's need a mixer when you can do everything a mixer does on a laptop?
Because DJ's are trying to sell an image. That image is based on their looks and on their stage performance. While they could do everything from a laptop, if they are performing in front of a crowd, and not from a booth, they will use the turntables as opposed to a laptop.
Why 2 mixers in VHF diagram?
In a VHF (Very High Frequency) diagram, two mixers are typically used for frequency conversion to improve performance and selectivity. The first mixer down-converts the incoming VHF signal to an intermediate frequency (IF), allowing for better filtering and amplification. The second mixer can be utilized for further processing or to shift the signal to a different frequency band. This dual-mixer setup enhances the overall system's sensitivity and dynamic range, enabling more effective signal processing in communication systems.
What is the significance of the ratio?
Gyromagnetic ratio is essential to some medical technologies like MRIs. This is because the higher it is, the higher the resonance and frequency are, which both affect the image.
If a radio station is tuned at 1600 kHz what is the image frequency?
Assuming that the receiver uses a high-side local oscillator and an IF of 455 KHz, the image frequency is 910 KHz above. When tuned to 1600 KHz, the image frequency would be 2,510 KHz.
What does fs mean on mixer?
fs may refer to sampling frequency which is the frequecy used to sample an analog signal.
What is band limited image?
A band-limited image is an image that contains only a limited range of spatial frequencies, meaning it has restrictions on the maximum frequency components present. This concept is important in image processing and compression, as it ensures that the image can be accurately reconstructed from its sampled data without aliasing. Band-limited images typically retain essential features while discarding high-frequency noise and details that may not significantly affect perception. This property is essential for efficient storage and transmission of images.
What is frequency in image processing?
In image processing, frequency refers to the rate at which pixel values change in an image. High-frequency components correspond to rapid changes in intensity, often associated with edges and fine details, while low-frequency components represent smoother areas and gradual intensity changes. Frequency analysis, such as through the Fourier Transform, allows for the separation and manipulation of these components, enabling techniques like filtering and image enhancement. Understanding frequency is crucial for various applications, including compression, noise reduction, and feature extraction.
