PLL data output, Horn control | Kenwood TK-940 specification

CIRCUIT DESCRIPTION

6-4. PLL data output

PLL data is output fronl DATA (pin 61), EIUABLE (pin 591, and CLOCK ( p ~ n60)of the CPU (IC2091. The sig- nas are input to the PLL IC (ICli when the channel is changed or when transmission is changed to reception and vice versa.

6-5. Horn control

The horn switch, consisting of Q13, 014, and Q29, controls the horn relay. It is supplied by the dealer to provide the external horn alert function.

0 2 9 disables horn alert, turning on when its base is high, to inh~bitthe function. Normally, the output from lClO is low, and 0 1 3 is off; the baseof 0 1 4 is about OV and 0 1 4 is off. When horn alert is enabled, the output from lClO goes high and Q13 turns on. The base current flows through RE1 to Q14 to turn Q14 on. Q14 can sink a minimum of 800mA.

6-6. Power supply circuit

D8 protects 1C1 against overvoltage. Each time a pulse comes from the PSW terminal, the IC1 output is reversed. The reversed output signal passes through 0 1 and Q3 and drives 0 4 . A voltage must be applied to the IGN terminal.

If 24V is supplied to the transceiver by mistake, Q2 turns on, and 0 3 and 0 4 are forced off, so the transceiver does not turn on.

BO		1	-
		T
		D8	LO
		AVR	LO
		AVR	LT
			a+
Q27			IC1
Q27			0 1
-	SW	DEF	SW
	SW	DEF	SW

8c HOR

0 13

014

Q29-

R2 R16

IGN

Fig. 8 Horn control circuit

If the SB terminal of the modular jack to which the microphone is connected is shorted or an overcurrent flows, R122 and R123 convert the current to a voltage and 0 3 0 turns on. Its output drives 0 2 8 and turns Q27 on, and the IC1 output foes high. This turns the transceiver off. If the terminal is no longer shorted, the transceiver can be turned on by pressing the power key. R125andC161 are used to prevent malfunction- ing when a device with a large surge current is connected.

SW	-			SB
SW
	4)	R122,I R123		= SB
	4)	vAvA,		= SB
03		030		(To rectangular
03		030		receptacle)
				receptacle)
SW	- SW		-

PSW

Fig. 9 Power supply circuit

TK-940 specifications

The Kenwood TK-940 is a highly regarded mobile two-way radio that has earned a reputation for its ruggedness, reliability, and excellent communication capabilities. Designed for professionals in various sectors such as public safety, transportation, and construction, the TK-940 incorporates advanced technologies to meet the demanding needs of users in the field.

One of the standout features of the TK-940 is its robust design, which complies with military specifications for durability. Its construction allows it to withstand harsh environmental conditions, making it suitable for outdoor and challenging work environments. The radio is also equipped with a water-resistant casing, ensuring that it can function reliably even in wet conditions.

The TK-940 operates in the VHF frequency range, providing wide coverage and strong signal penetration. With a power output of up to 110 watts, users can achieve long-range communication, essential for coordinating activities over large areas. The radio supports both analog and digital modes, allowing seamless integration into various communication systems while maintaining high audio clarity.

Another significant feature of the TK-940 is its enhanced audio quality. The radio is equipped with Kenwood's advanced noise cancellation technology, which minimizes background noise and ensures clear voice communication even in noisy environments. The audio output is powerful and adjustable, catering to individual user preferences.

Moreover, the TK-940 supports a variety of signaling options, includingDTMF, MDC-1200, and 2-Tone/5-Tone signaling, facilitating efficient communication. These signaling features enhance interoperability with other communication devices and systems, allowing users to communicate seamlessly with teams or dispatch centers.

Kenwood has also incorporated user-friendly functionalities into the TK-940. It boasts an intuitive user interface with programmable buttons, enabling quick access to essential features. The large, backlit display provides clear visibility and is easy to read in various lighting conditions.

The TK-940 is designed with safety in mind, featuring emergency alerts and lone worker protection, ensuring users can communicate their status in critical situations. Overall, the Kenwood TK-940 is a powerful and versatile mobile radio that combines durability, advanced technology, and user-friendly features, making it an ideal choice for professionals who require reliable communication in the field.

Kenwood TK-940 service manual PLL data output, Horn control, Power supply circuit

Models: TK-940