Modulation driven ssb modulator

Status
Not open for further replies.
H

hosein_rabiee_g

Member level 2
Joined
May 9, 2010
Messages
53
Helped
8
Reputation
16
Reaction score
8
Trophy points
1,288
Location
IR
Visit site
Activity points
1,550
Hi everybody.
I want to shift the frequency of a signal. One solution is using a SSB modulator and a DDS for making sin and cos of frequency shift. But because of variable power of RF signal, the mixer (modulator) should be driven by IF port.
I find the modulation driven ssb modulator only at miteq. do anybody have an experience or can propose a device?
May I use image reject mixer such as hmc523?
 

If you are looking only to shift the frequency, any RF mixer would follow at its IF output the RF input level, if the mixer is not in compression (RF input level is below P1dB of the mixer).
So, you can use any standard DBM (double-balanced mixer) which will preserve your modulation and levels.
 

How much do you need your frequency shifted? As above, a mixer is a conventional solution. You also need a local oscillator, and filters.
 

The RF power and frequency is variable and i want to shift the frequency 100 kHz ~ 1 MHz. and so i cant use a mixer in conventional configuration.may i drive any DBM from IF port?
 

In most of the DBM mixers using diodes the RF port can be swapped with IF port.
Anyway, is not very clear for me what you want to do exactly...
 

hosein_rabiee_g said:
The RF power and frequency is variable and i want to shift the frequency 100 kHz ~ 1 MHz. and so i cant use a mixer in conventional configuration.may i drive any DBM from IF port?
Click to expand...

Yes, you can. Make sure mixer diodes are driven by the nominal power usually coming from LO port.
Small frequency shifts like in your case will generate unwanted responses that are nt removable by filters.
Google "frequency shifters", some manufacturers offer such devices optimized for small shifts.
 
vfone said:
In most of the DBM mixers using diodes the RF port can be swapped with IF port.
Anyway, is not very clear for me what you want to do exactly...
Click to expand...

I want to swap the LO port and IF port and drive mixer with IF frequency signal.

- - - Updated - - -

thanks for reply.
The maximum source and sink current of IF port of HMC523 is 3mA and it is not sufficient for driving mixer.
But in the DBM configuration, the IF and LO ports are swapable. so do you think i can use this device?
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…