what is the acronym "IF"?

Thread Starter


Joined Oct 3, 2010
refer to this datasheet. page 53, the descriptions for:
and in several locations throughout this datasheet refer to IF. What is it?
I've scoured the datasheet and can't find a definition and google only returns "If" statements in programming languages.



Joined Apr 5, 2008

IF stands for Intermediate Frequency.
from page 11:

2.2.1. Analog Sound IF Input

The input pins ANA_IN1+, ANA_IN2+, and ANA_IN−
offer the possibility to connect two different sound IF
(SIF) sources to the MSP 44x0G. The analog-to-digital
conversion of the preselected sound IF signal is done
by an A/D-converter. An analog automatic gain circuit
(AGC) allows a wide range of input levels. The high-
pass filters formed by the coupling capacitors at pins
ANA_IN1+ and ANA_IN2+ (see Section 7.4. “Applica-
tion Circuit” on page 99) are sufficient in most cases to
suppress video components. Some combinations of
SAW filters and sound IF mixer ICs, however, show
large picture components on their outputs. In this case,
further filtering is recommended.


Joined Jun 29, 2010
Let start with some basic view:-

Two types of radio receivers were invented Tune Freq. was the first in which there was some disadvantages like quality factor,etc....
then come IF which is called Intermediate freq. in this Receiver the received freq. is lowered by a oscillator called local Oscillator in receivers. the overall freq. is now less than received.

Why should we bother of low freq.??

B'coz low freq. can be easily handle than high freq. nowadays almost all receivers have build in local oscillator which is tuned with Gang called Variable capacitor.
the disadvantage of Tune receivers can be over come but the DE-merit of this receivers is Image Freq. ( something like this) .......

E.G.:- FM receivers, LNB in DTH ( low noise block called Feed horn) you can see the circuit in feed horn which converts GHZ freq. to MHz ( 9750 or 5150Mhz)

Google for more Explanation.


Joined Apr 24, 2007
Using an IF is also nice because from the IF-conversion point onward in a receiver the frequencies are always the same, and it's MUCH easier to design things for a fixed frequency that's known in advance.


Joined Apr 7, 2010
TRF, or tuned radio frequency radios were probably first on the scene. The one I remember had 3 different tuning dials.
Regenerative sets were probably next in line.
Superheterodyne receivers were the latest developement (until IC's came along). The AC/DC "All American 5" mixed the incoming 550khz-1600khz signal with a higher frequency local oscillator. The resultant 455khz IF frequency was then amplified and processed into audio. FM receivers were the same way except their IF frequency was 10.7 mhz. Because they only had one mixer, these were called single conversion radios. My big old Hallicrafters shortwave radio was double conversion. The first IF frequency was 10.7mhz and the second IF frequency was 455khz.

My all time favorite radios were my 1A5 grid leak detector receiver made in a cigar box and a 12AT7 super-regen aircraft receiver.


Joined Apr 7, 2010
what is this....??
I have seen up loader video/channel in you tube ....
An "All American 5" is a slang name for 5 tube (or valve) AM band superhet radio receiver that was line powered with no isolation transformer.

12BE6 mixer
12BA6 IF amp
12AV6 detector/1st audio
50C5 audio output
35W4 half wave rectifier

There were so many models of this type made by so many manufacturers they could quickly and easily be repaired because the technician had pretty much memorized the basic schematic. After doing a few hundred it begins to sink in. Kinda sorta like knowing what pins 2,3,4,6, and 7 are on an op-amp.
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