Connect with us

10.7 MHz oscillator with transistor

Discussion in 'Radio and Wireless' started by aurelZ, Jul 17, 2019.

  1. aurelZ

    aurelZ

    64
    7
    Jun 10, 2019
    Really?
    I don't know from where you digg all that observation in a shape like "WallOfText"
    Just to let you know ,i finished my high electronic school somewhere at the end of 1988.
    And from then to now i have build many electronic projects.
    fixing many electronic devices,TV,Receivers etc
    So i am surprised about simple thing as is ceramic filter for 10,7Mhz which you can find
    in almost any analog FM radio receivers ,car radios,satelitte receivers and i really don't get it what kind of data you need.
    Here is the image of ceramic filter i use
    MURATA_E10_7J.gif
     
  2. Audioguru

    Audioguru

    2,618
    593
    Sep 24, 2016
    The very simple 10.7MHz oscillator you posted in post #15 has an output which is AM and FM combined so it is a poor way to test an FM demodulator that is supposed to reject AM.
     
    chad786 likes this.
  3. aurelZ

    aurelZ

    64
    7
    Jun 10, 2019
    AM and FM combined so it is a poor way to test an FM demodulator that is supposed to reject AM.

    Yes Audioguru , i can agree with that but don't forget that main purpose of
    FM detector to pass only one carrier frequency which is 10.7 and as such this circuit is the
    simpliest soulution.
    In the past you must know there are some electronic kit-s with such a option.
    As far as i can say ,for me this topic is finished.
    all best...
     
  4. majoco

    majoco

    50
    8
    Nov 10, 2019
    Never mind connecting the oscillator to an FM IF amplifier - do you have a shortwave receiver, preferably digital, that you can use to search for your oscillator around 10.7MHz? Much better than a frequency counter as when you connect the counter to your oscillator, the frequency will change! I use a cheap Degen 1103 digital receiver for all sorts of things, setting the frequency of a tube signal generator, for example - very quick and easy, just listen for the carrier with the radio set to "SSB" on the frequency you want.
     
  5. bertus

    bertus

    119
    41
    Nov 8, 2019
    davenn likes this.
  6. aurelZ

    aurelZ

    64
    7
    Jun 10, 2019
    problem is already solved,look lat schematic
     
  7. WHONOES

    WHONOES

    741
    152
    May 20, 2017
    Had a look at your link and cannot find any mention of a ceramic trans-filter. Ceramic filter yes, trans-filter no.
     
    chad786 likes this.
  8. davenn

    davenn Moderator

    13,347
    1,774
    Sep 5, 2009

    yeah, we had that one out earlier in the thread
    Trans-filter seems to be some sort of screwball local definition to the OP
    Everywhere else in the world of electronics they are known as ceramic filters :)
     
    hevans1944 and chad786 like this.
  9. hevans1944

    hevans1944 Hop - AC8NS

    4,258
    2,008
    Jun 21, 2012
    Everything that you need to know about ceramic filters can be found on this web page, along with links to other sources of information. Until these spiffy little devices came along, the filters they implemented were made from discrete quartz crystals, hand tuned to specific frequencies. It was an expensive and time-consuming process, so the filters were not cheap. Collins Radio came along later with their patented mechanically resonant filters, which were inexpensive but restricted to a much lower range of frequencies, typically 455 kHz, which was associated with single-conversion super-heterodyne receivers tuning from the AM broadcast band up to about 30 MHz. More about Collins filters here.

    Above 30 MHz or so (there are no sharp boundaries) 10.7 MHz is a popular super-heterodyne intermediate frequency (IF), especially for broadcast band FM receivers. Communication receivers sometimes use it before down-conversion to a lower IF such as 455 kHz. This makes ceramic filters very much a popular design component for RF signal processing such as band-pass and band-stop filtering. However, I doubt anyone skilled in the art would ever seriously consider using them as a stable frequency-determining element. Better, simpler, more frequency-stable circuits are available. As usual, your mileage (or kilometers) may vary. Use whatever works for you.
     
    davenn and bertus like this.
  10. majoco

    majoco

    50
    8
    Nov 10, 2019
    VHF FM IF amplifiers need a bandwidth of about 180kHz (as shown on that MuRata pic) so how do we know where in that 180kHz the thing is oscillating?
     
    duke37 likes this.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-