Indicate the false statement. Noting that no carrier is transmitter with J3E, we see that

Solution (By Examveda Team)

J3E refers to a transmission mode where the carrier is suppressed, commonly known as single-sideband (SSB) transmission. In J3E, only the modulated sidebands (upper or lower) are transmitted, and the carrier signal is omitted to save power and bandwidth.

Here’s the detailed explanation for each option:

Option A: The receiver cannot use a phase comparator for AFC
This statement is true. In J3E transmission, there is no carrier signal, so phase comparators cannot be used for Automatic Frequency Control (AFC). AFC typically relies on a stable carrier signal to detect and correct frequency errors. Since J3E involves suppressed carriers, the receiver cannot use traditional phase-based methods for frequency control.

Option B: Adjacent-channel rejection is more difficult
This statement is true. Since J3E transmission lacks a carrier signal, it becomes more challenging for the receiver to reject adjacent channels. The absence of a carrier signal means the receiver has to rely more on sideband characteristics to isolate the desired signal, making adjacent-channel rejection more difficult.

Option C: Production of AGC is a rather complicated process
This statement is true. Automatic Gain Control (AGC) typically requires a stable signal or carrier to adjust the receiver’s gain based on signal strength. Without the carrier in J3E transmission, producing AGC becomes a more complicated process, as the receiver must deal with varying signal strengths without a reference carrier.

Option D: The transmission is not compatible with A3E
This is the false statement. A3E refers to a transmission mode that uses amplitude modulation (AM), including a carrier. J3E (SSB) and A3E (AM) are compatible in the sense that a receiver designed for one can still receive the other. However, the demodulation process might differ due to the absence of a carrier in J3E. Despite these differences, the transmission is still compatible, and this statement is false.

Therefore, the correct answer is Option D: "The transmission is not compatible with A3E."