Followups

Original F-16 used analog FBW, so the original 8 European nations that uses F-16 prohibits their F-16 from flying too close to radio broadcasting towers, cuz interference was too strong & may lead to crash. DFBW is governed by military standard of USA, the MIL-STD-1553.

In addition to replacing analog signal w/ digital ones in the Cu wire, DFW includes Fly By Light (FBL) & Fly By Optics (FBO). Both of these replace Cu wire w/ fiber optics, & using laser to pass info, also in the form of 1 & 0. The advantage of using fiber optics & laser is that it's totally immune to electromagnetic pulse interference, such as those produced by nuke explosion or lightning. Fiber optic is governed by military standard of USA, the MIL-STD-1773, & like MIL-STD-1553, it is internationally accepted standard.

The difference between FBL & FBO is that the former only includes flight control (FBW replacing the hydraulic-mechanical control), while FBO also including using fiber optics in navigation, namely, in the Inertial Navigation System (INS), in addition to flight control.

FBO uses fiber-optic gyro while FBL uses laser gyro. Advantage of optic gyro over laser gyro is that due to the phyical property of light, when light entering at angles less than the critical value, it disappears, laser gyro has this problem. Optic gyro has all the advantage of laser gyro, but doesn't have this problem, cuz in optic gyro, laser is contineously reflected w/i the fiber optics, thus avoiding the problem.

However, optic gyro is extremely difficult to make, & currently, only USA can make it, Littion Industries, to be exact, the only company in the world, while several European nations can make laser gyro.

my friend has put up a question:

"The F-15E OTOH uses only partial FBW for its
onboard Control Augmentation System (CAS), Automatic Flight Control System
(AFCS), and Pitch Trim Compensator (PTC). The CAS stabilizes G-forces during
normal flight while the PTC as the name suggest, trims the aircraft to maintain level
flight without any pilot input. AFCS adjusts for unbalanced weapon or fuel loads, or
engine malfunctions as well as aircraft performance under difference sped and
altitudes. Meaning that the pilot will get the same response from the aircraft when
he pulls on his flight stick at 300 knots/1,000ft, then when he does the same at
600kts/30,000ft. Pretty cool if you think about. The pilot no longer has to worry
about the regular nuances of flight in a non-FBW aircraft.

However despite all this, I believe the F-15E is said to not have a complete FBW
system. Do you know why that would be the case? "

how are you? Continuation to your reply of FBW/FBO system:
"Are there any aircraft currently in production or serving that utilize complete digital
FBW? I know the F-16 was the first aircraft to incorporate complete FBW, but as
you say, it is analogue in nature. The F-15E OTOH uses only partial FBW for its
onboard Control Augmentation System (CAS), Automatic Flight Control System
(AFCS), and Pitch Trim Compensator (PTC). The CAS stabilizes G-forces during
normal flight while the PTC as the name suggest, trims the aircraft to maintain level
flight without any pilot input. AFCS adjusts for unbalanced weapon or fuel loads, or
engine malfunctions as well as aircraft performance under difference sped and
altitudes. Meaning that the pilot will get the same response from the aircraft when
he pulls on his flight stick at 300 knots/1,000ft, then when he does the same at
600kts/30,000ft. Pretty cool if you think about. The pilot no longer has to worry
about the regular nuances of flight in a non-FBW aircraft.

However despite all this, I believe the F-15E is said to not have a complete FBW
system. Does anyone know why that would be the case? "

The textbook definition (or as close to it as I can remember - getting old) of an analog system is one in which the value of an electrical signal is directly analogous to a quantity in the physical world it represents. A common example would be the traditional stereo. The signal coming out of our amp is an analog representation of the music.

In analog FBW, control and feedback signals between the cockpit and control surfaces are carried more or less like z described. However, voltage is not necessarily used. Current loops are used in industrial applications because it is more resistant to EMI. I don't know if any FBW uses that technique, though.

I'm not sure whether these signals are digitized by the FBW computer for calculation purposes. I would guess so because it would be quite difficult to build an analog computer to handle the load, especially in a relaxed stability design.

Digitized FBW (DFBW) uses 2 digits, 0 & 1 to represent low & hi, so mathematically, the voltage graph is consisted of 2 parallel broken lines, one being 0, & the other being 1. Anything that's not these 2 r rejected,

To be precise, two voltage ranges are defined for 0 and 1 respectively. If you don't have enough tolerance, it's not gonna work.

so DFBW is more resistant to interference.

More importantly, the digital channel allows the use of error correction coding. Even if a message is corrupted due to EMI, it can be detected and repaired or rejected accordingly.

the advantage of using fiber optics & laser is that it's totally immune to electromagnetic pulse interference

The optical link may be immune, but the fiber-optic transceivers and the rest of the electronics are still equally susceptible to EMI and must be protected. Use of fiber just moved the weakest link somewhere else in the system.

Acutally, I'm a quality assurance engineer in aerospace/aeronautic industry, mostly involving avionics.

As for comprehensive info, Jane's Information Group is a very good source, which has many publications, & the 2 u should look r:

1). Jane's all the World's Aircraft

2). Jane's avionics

However despite all this, I believe the F-15E is said to not have a complete FBW system.
Does anyone know why that would be the case? "

What we mean FBW usually means the system that is directly used for controlling surfaces, other systems such as INS, PTC, etc. r not included, and these systems can still be analog (though more & more, they r digitized). In this narrow definition, F-15E is completely FBW.