Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

[SOLVED] problem with sensitivity of SA615

Status
Not open for further replies.

xandeyes

Junior Member level 1
Joined
Nov 22, 2013
Messages
17
Helped
1
Reputation
2
Reaction score
1
Trophy points
3
Activity points
138
hello everyone.
i have problem with sensitivity SA615.
my input frequency is 21.4MHz ( modulation 1KHz audio,lever 5.6kHz) and IF = 455KHz . the crystal OSC is 20.945 MHz

I rematching RF input, use ADS simulation and after installation, I measure with VNA , equal S11 = -15dBm ( at 21.4MHz)
the circuit attached below.

But the sensitivity very badly,measure,adjust the inductors and equal = 90uV ( at 12dB SINAD)

I had some experience to adjust IC FM/IF MC3361 ( RF input 21.4MHz , IF 455KHz and sensitivity about 3uV at 12dB SINAD )
therefor I know how to adjust quadrature detector terminal.

the datasheet SA615 show sensitivity achieved 0.22uV and how can I have this value with my RF input???

thanks so much.

// i use ceramic filter is murata cfukf455ka2x-r0
sa.PNG
 

Edit :It doesn't need a differential input, I didn't see..
 
Last edited:

Assuming the crystal is right on 20.945 MHz, and the output resonator resonates on 455 KHz, I recommend to replace the 455 kHz filters with 100pF capacitors, just to see if you get the sensitivity.
Otherwise should be no reasons the circuit don't work.
 

thank for your replies. I will to try replace filters...
 

sorry for long time I don't reply because I havn't time.
my problem is in the power supply. I have a capacitor 47uF close PS but too far with IC. If I add a capacitor close vcc pin, the sensitivity is very well.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top