homodyne & heterodyne

[watertreader]

homodyne heterodyne

Hi,

Just want to have some verification of my understanding of hetereodyne and homodyne.

Heterodyne means mixing the signal with another signal of different frequency and homodyne means mixing with another signal of same frequency. Is that right?

Btw, what is the respective uses of both? I have always seen heterodyning as a mean to improve signal but what about homodyning?

Thanks for your help!

 

[electronics_kumar]

homodyning.doc

another name for homodyne method is Synchronous detection.......

 

[SkyHigh]

heterodyne means

Hi,

Just want to have some verification of my understanding of hetereodyne and homodyne.

Heterodyne means mixing the signal with another signal of different frequency and homodyne means mixing with another signal of same frequency. Is that right?

Btw, what is the respective uses of both? I have always seen heterodyning as a mean to improve signal but what about homodyning?

Thanks for your help!

Well... Not wrong, but you have a vague idea of homodyne and heterodyne.

Homodyne only allows one frequency from the LO to mix, not actually because it can uses the same frequency. This is due to the homodyne architecture (direct conversion or zero-IF) that uses only one mixer stage after the LNA.

Homodyne has several drawbacks. It suffers from DC offset and baseband saturation due to LO leakage into the mixer and the RF front-end. The only baseband filter is the output I-Q filter and it has to be very steep. These issues are not easy to solve.

Heterodyne has one more mixer stage than homodyne. This allows heterodyne to use different frequencies from any LO to mix. Should the particular LO used has increased in price, you are not locked to its component supplier. You can simply choose to use a different LO at different frequency for mixing. Hence the heterodyne architecture permits flexibility in changing the LO for capturing different RF bands.

Heterodyne has drawbacks too. It has image frequency and it has a higher component cost than homodyne.

Homodyne is found in narrowband AM radio at very low cost. It is also found in walkie-talkie of one or a few radio channels.
Now it is found in RFID.

Heterodyne is found in multi-band mobile phones, AM/FM radio, VHF/UHF TV, Satellite receiver, and even advanced walkie-talkie (with anti-jamming capabilities). A better example is the Bluetooth, WLAN, CDMA, GSM, W-CDMA transceiver.

 

[mshareef]

heterodyne

Hi,

Here is a good explanation of (homo & hetero)dyne methods

www.hep.ucl.ac.uk/~liapine/ part_three_analog_signal_processing.doc

 

[zharaa]

understanding heterodyne

hi
look at this site
https://www.thevalvepage.com/radtech/synchro/synchro.htm

 

[ittefaq11]

why use heterodyne architecture for cdma

@mshareef

d link u gave is not wrking