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89 Threads found on Input Signal Mixer
Going to the original question: "Can you tell me are two gate's are interchangeable?" The answer is: Depends by your application. Originally the Dual-Gate MOSFET was invented to get a gain-controlled device (input signal on G1, and DC gain-control on G2). Also this device can be used as an RF mixer, applying two RF (...)
I have a question on the effect of IM2 vs IM3 in I or Q-channel individually, versus at complex baseband: In a quadrature downconverter, assume each path (I or Q) contains an LNA and mixer which contribute IP3 or IP2. The IM3 from the LNA is at the input to the mixers, so the IM3 along with the signal undergo complex (...)
A balanced diode mixer is the usual solution to modulate a RF input signal with +/- 1. Or a balanced active modulator. "Modulating LNA" sounds counter-intuitive, because an amplifier is expected to have a defined gain sign, either positive or negative which doesn't depend on the power supply.
Is nothing wrong with your simulation. This a normal behavior of the conversion loss vs LO input power in a mixer design. But I think there is a spelling mistake in your post. You mentioned twice about IF input power. Actually IF should be an output signal, which results from mixing RF input (...)
I meant the tail transistor. Sorry about the typo. For higher linearity, input gm must be as linear as possible.
mixers are generally driven hard by LO port and impedance matching is not necessary because input impedance is very variable at LO port due to hard driven rail to rail swing signal level.Matching can be considered for RF/IF port so small signal input impedance can be taken into account.However matching is (...)
Hi! I decided to solder a 3.5mm 4-pol phone connector to a 6.35 mm one in order to record electrical instruments (guitar, keyboard... maybe mixing desk too) directly in my smartphone. You can see the first version of this "adapter" in the picture attached. 125598 I used it together with two apps (MyVoiceFree and Wav
input Matching is simply like LNA matching so Conjugate Matching.LO port is hardly driven so it doesn't need matching. Output Matching can be done by obtaining large signal output impedance ( Large signal S-Parameters ) then apply a proper Conjugate Matching or Harmonic Matching that decreases harmonic contents at the output.( It's a little (...)
Hi, I have designed a PLL that can output square waves as well as sine waves (by adding filters). The signal of the PLL should go to a mixer that will transmit the LO+ signal when its data input is '1' and transmit LO- signal when data input is '0'. Overall the output of the (...)
I guess you're working on a I/Q Demodulator, right ?? If it's so, characterizing I/Q outputs is not very interesting( relatively low frequency) .If LO level is sufficiently high, LO port can be neglected.( Matching is not must because this port is hardly driven) For RF input, you'll need a-at least-small signal s-parameters to match to LNA output.
Because you still get the mixing process, but with gain about 15dB lower than should be, for me looks like one of the RF or LO inputs lost the balanced configuration. The gain of the mixer is easy to calculate. The difference between RF signal input in dBm, and IF signal output also in dBm, is the gain (or (...)
If the internal transistors of the Gilbert cell mixer are not biased to work in saturation (and in SA612 case, they are not) is preferable to drive the mixer at the LO input using a sine wave signal. There are many switching-type mixers where is mandatory to use square LO signal, but this is (...)
The post is insonsistent regarding intended circuit function. It's also unclear how the waveform has been acquired. I think, the mixer circuit can be also described as an AM modulator because part of the output signal is a product of both input signals, but only a small part.
In additional to the comment above, Check also LO driving signal amplitude to prevent self-mixing due to limited LO-RF isolation.If this amplitude becomes very high, LO mixes with itself at the RF input then it can generate a modulation by some phse shift.
The result is that both components, RF and LO are multiplied in a mixer, and the IF input contains the result of this product. If you need a clean translation of the "high" RF signal in the "low" IF output, use the best LO oscillator you can find. Otherwise by applying a dirty LO you get a dirty IF output. Oscillator noise problems has bee (...)
Hi there. I want to use a frequency mixer with a LO power of 6 dBm and an expected RF input of -60 dBm. If the specified LO-RF isolation is 35 dB, what would be the effect of this insufficient isolation? Would there still be an IF output of |Frf-Flo| at a lower power or would this not be seen at all? Thanks
Due to limited selectivity of the RF filters, RF gain can't be arbitrarily high, otherwise off-band components could cause amplifier and mixer overload. So if you plan higher RF gain, you have to check that the signal is keeping the linear range in every part of the receiver. When we said that the RF amp has input power is -110dB
i don't think that a superhet with an IF of 455kHZ will work with an input signal of 457 kHZ. If it is going to be for a fixed (457 kHZ) reception only, I would use a domestic superhet with the mixer/oscillator re-configured as an RF amp. Get an old one with IF transformers and not fixed ceramic filters (can't change the frequency of (...)
Hi ! I am making an RF Transmitter and i have a problem with power leakage for LO port to IF port and RF port. I don't know what to do and i am little confused about how can i fix this. Source(-10 or -20dBm) 10KHz --------->mixer conv.loss=8db--------->RF port and L.O=70MHz and 7dbm I put an oscilloscope to mixers input IF and i (...)
I may want to use my spectrum analyzer for the job. The noise source operates with a pulsed input only, or can i apply a constant 28V DC to produce the hot noise?
Hi biff44 again. So, after the mixer i put one filter to cut the unwanted zone. So instead the mixer and the filter you propose a single modulator. As i understand the SSM wil need also a filter to cut the unwanted L.O freq=30.1MHz. So why a SSM and not a mixer? Also the SSM that i see here
Perhaps you are talking about this sentence in the article? "The mixer should be able to take in an input peak of 1V and have a conversion gain..." I believe 1V means the incoming signal from a previous stage (amplifier). This is typical line level amplitude. I see resistors labelled what looks like 'Rbias'. Their values are not stated in (...)
In a multiple conversion receiver each mixer (or mixing process) would have its own image frequency, whatever is the 1st, the 2nd, or the 3rd in the chain. An image filter placed in the front of a mixer will suppress the image signal AND the image noise. Usually the 1st mixer use at its input (RF (...)
in designing down converter mixer, how to determine RF input power needed? Most of designing circuit they chose -30dB. thank you
I am designing a mixer that produces a differential output based on differential inputs from an LO and RF. My question is what is a differential input/output signal? The differential outputs are generally labelled IF+ and IF-. Does this mean the signals are just inverse of the other? If this is true why cant (...)
Hello kemiyum, Thanks again for your support. Regarding 1): what do you mean with ?this option is often implemented on their hardware?? Are you saying that the most spectrum analyzers have already a decoupling cap there? Or I should provide it? I was checking the manual of one analyzer now, and on its input, it is written: 50 ohms, 0 VDC, D
Hi, I have a transmitter sending a continuous wave at some channel in the ISM band, 902-928MHz. Can this signal be used as a input to the mixers on the receiver, instead of an LO?
A mixer is in principle a multiplier; it multiplies for instance the local-oscillator signal with an IF input signal. Then pairs of multiples are generated in frequency spectrum. We typically choose one of them, name it RF and use filters to suppress all others. Such action is named "upconversion" and can be used to (...)
Consider the quadrature mixer as shown below. The frequency domain representation of the input signal x(t), X(f) is as shown below. Assuming that f2>>f1>>fb, draw the frequency domain representation of the signal at points a, b, c, d and e. 64380 I am not asking you to do this for me. I would maybe like someone to
Hello Every one, I want to design a analog mixer with 0.18um BICMOS process. The mixer is used to be one module in the whole chip. One input signal of the mixer is a wide-band signal, for example , its bandwidth is 50MHz. The center frequency is variable between DC and 2GHz. The other (...)
Hello, I am finding trouble in simulating the ouput of a mixer. I have two input waves one of the frequency 400.001Mhz and other input of freq 400Mhz. I need to select the 1Khz signal from the mixer output, so I placed a low pass filter after the mixer, so as to obtain the 1Khz (...)
As Zorro wrote, a mixer needs its diodes to be "pumped" by a LO input power. LO power drives AC and DC current through the diodes, alternatively opening and closing them. When you inject a low-level RF signal into it, the diode non-linearity around the I/V "knee" will generate harmonic combinations of the LO and RF frequency. Some of then (...)
kapil86 let's start from the basics: a mixer is a device that up/downconvert a signal. You should have an input LO signal, and input RF signal and an output that in you case is RF+LO and RF-LO. I'm assuming that you have RF=2400MHz, LO=2398MHz and IF=2MHz. Could you please confirm? There (...)
Hello, is any one can guide me to built a costas receiver. At the input of a mixer the LO and RF signal creates an IF signal. This IF is the frequency difference of LO and RF irrespective of their position of frequency spectrum, i mean IF=LO-RF or IF=RF-LO. I need to track this IF signal at the output of (...)
Hi, so the input signal must be sampled at IF (70 MHz) and feed to the first stage up-converter witch will translate it to IF_2 (800MHz-2GHz) wich in turn will be feed to the second stage mixer/upconverter so that it will be translated to the desired 30GHz band. LO_1 = (800MHz-2GHz) - 70MHz LO_2 = 30GHz - (800MHz-2GHz)
In Gilbert mixer, People usually said large LO signal and Small RF signal. Any one give a detail example, what's the swing value of LO & RF signal.?? Thank you very much
Hi, A subharmonic mixer will use the first harmonic (in most cases) of the LO signal you input in the mixer to mix with your IF. Let take an example: We use a subharmonic mixer, we come with a 10 Ghz LO signal in and a 1 GHz IF. The mixer will internally mix the 2*10 GHz (...)
Does it matter if the local oscillator amplitude on a mixer input (about 9Vpp) is greater than than the IF on the other mixer input (about 3Vpp)? It is a diode ring modulator.
Hello all, I have a misgiving about the voltage conversion gain of mixers, That is defined as VIF/VRF, where VIF and VRF are the input and the output voltages of the (downconversion) mixer respectively. My question is- why this definition do not include VLO (the other input of the mixer)? Let me exemplify: (...)
I'm designing a receiver front-end with a double-balnaced Gilbert mixer. I found out the LO signal swing for down-converted mixer in my case is not enough. How can I improve the LO signal swing?? I've adopted a limiter between the LO and mixer switching stage input so far Replacing this (...)
Hi - I have a Gilbert Cell, mixing the signal from 7GHz directly to 0Hz. Now sweeping both phases of the LO input signals coherent, there are constellations where the mixer delivers negativ output voltage. Can the be explained? Greetings, Thomas
I am designing a low voltage(1.8V) Gilbert cell mixer, which includes(from bottom to top) tail current mos, RF input mos, LO switching mos, and resistive load. Since LO has large amplitude, there would be a large common-mode second harmonic of LO at the drain of RF input mos, which may cause the RF input mos to go into (...)
Hi, In receiver design, there is well known question, reciprocal mixing. The reciprocal mixing requirement is usually expressed as the interference product produced by reciprocal mixing is below or equal to the floor noise at the ouput when only the MDS(minimum detectable signal) is apply to the input. So the constraint on LO phase noise is PN=
Dear all, I have question about the frequency band conversion problem. I hope anyone explain it to me. In the up-conversion mixer, this is a quadrature input and differential output mixer. Then, the differential signal combines and gives out a single output. My problem is arisen. If a modulated (...)
Something is not ok. Even if you have a high insertion loss input filter (let's say 5dB) and a poor 2dB NF LNA, you get better than 14dB system NF. Download AppCAD software, go to signal-Systems/NoiseCalc and verify what is going wrong.
Dear all, I have question about the quadrature mixer NF simulation setting. I hope anyone could teach me. The attached picture is the NF simulation setup for quadrature mixer. In my design, it has two input ports (Port 1 and Port 2) and generate quadrature signal for the mixer (...)
Hello, a really basic question that confuses some of us. An RF mixer has 3 ports: LOSC RF IF In DOWN-CONVERSION: RF is the input IF is the output What about in UP-CONVERSION? Which port should be the input of the low frequency signal and which one the output of the high frequency (produced) (...)
How to use the analysis (ac small-signal analysis?) in modeling? Should be used balun with a symmetric input / output? Source power to choose a "analogLib -> port"?
mixers are nonlinear blocks and that's why small signal analysis are not valid including AC and s-parametrs.. Instead, a HB analysis by putting current meter can give you the input impedance of a mixer. Or transisent simulation will also give but I prefer to use HB..
You need a mixer that supports near DC on RF input as the one below. The topology will be: Low Pass Filter, mixer, LO (LO=IF-150Hz; IF can be anywhere in the mixer range), IF filter, IF Amplifier, etc.