AM receiver

Discussion in 'Homework Help' started by sima7, May 20, 2016.

  1. sima7

    Thread Starter New Member

    May 20, 2016
    7
    0
    hi
    i simulated a AM receiver circuit (shown bellow). transistor 1&2 are off but should be on . i don't know what to do?
    please hellp me.
    [​IMG]
     
  2. Robin Mitchell

    Well-Known Member

    Oct 25, 2009
    732
    199
    What frequency are you feeding into the circuit?
    What range of frequencies are you operating on?
    Care to share simulation data?
     
  3. sima7

    Thread Starter New Member

    May 20, 2016
    7
    0
    i attach spice schematic.
    f=500khz
    amp=1u

    Tanks.
     
  4. sima7

    Thread Starter New Member

    May 20, 2016
    7
    0
    Of course, the main circuit is
    [​IMG]

    just the name of elements are different and i changed the r4 10k ohm to 1kohm just for testing.
    someones set R2 , 2.2k and someones set 330 ohm.
    Q1&2 are off in this photo.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
    2,646
    631
    Why do you think Q1 and Q2 are "off"?
    Can you tell us the voltages across R2 and R5?
     
  6. sima7

    Thread Starter New Member

    May 20, 2016
    7
    0
    i also simulate the circuit with HSPICE .
    DC analysis is:
    **** bipolar junction transistors


    subckt
    element 0:q2 0:q1 0:q3
    model 0:bc109c-x 0:bc109c-x 0:bc109c-x
    ib 7.7651p -250.3103p 1.7210u
    ic 16.6853n 250.3032p 738.5131u
    vbe 369.9050m -369.9050m 651.0822m
    vce 8.8818 8.5413 1.5977
    vbc -8.5119 -8.9112 -946.5764m
    vs -8.8818 -8.9112 -1.5966
    power 148.1988n 2.2305n 1.1810m
    betad 2.1488k -999.9718m 429.1066
    gm 639.2468n 24.0493f 28.7194m
    rpi 133.7118x 5.239e+13 16.7054k
    rx 0. 0. 0.
    ro 2.2301g 9.601e+14 39.3839k
    cpi 13.8119p 9.8936p 28.1532p
    cmu 2.2225p 2.1914p 3.9691p
    cbx 0. 0. 0.
    ccs 0. 0. 0.
    betaac 85.4749 1.2602 479.7693
    ft 6.3448k 369.6009m 142.2952x
     
    Last edited: May 20, 2016
  7. sima7

    Thread Starter New Member

    May 20, 2016
    7
    0
    netlist:


    c2 m 0 100n ic=10m
    c3 vc2 b3 100n ic=10m
    c4 vc3 n 100n ic=10m
    c5 vcc 0 10u ic=10m
    c6 vc1 0 100n ic=10m
    c7 vi m 500p ic=10m
    l1 vi m 200u ic=10m
    r1 m vc2 100k
    r2 e1 b2 1k
    r3 vc1 vc2 330
    r4 vc3 b3 550k
    r5 vcc vc3 10k
    r6 n 0 25
    r7 vcc vc1 1k
    vcc vcc 0 9
    q2 vc2 b2 0 BC109C-X
    q1 vc1 vi e1 BC109C-X

    q3 vc3 b3 0 BC109C-X
    .model BC109C-X NPN
    +Is=7.049f
    +Xti=3
    +Eg=1.11
    +Vaf=28.14
    +Bf=677
    +Ise=7.049f
    +Ne=1.38
    +Ikf=96.23
    +Nk=0.5
    +Xtb=1.5
    +Br=2.209
    +Isc=250.3p
    +Nc=2.002
    +Ikr=10.73
    +Rc=1.433
    +Cjc=5.38p
    +Mjc=.329
    +Vjc=.6218
    +Fc=.5
    +Cje=11.5p
    +Mje=.2717
    +Vje=.5
    +Tr=10n
    +Tf=437.8p
    +Itf=3.097
    +Xtf=12.85
    +Vtf=10
    * PHILIPS pid=bc108c case=TO18
    * 91-08-02 dsq
    *$


    vi vi 0 sin(0,1u ,500k)

    .op
    .tran 1u 50m
    .end
     
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