FA_17GHz_PRESCALER.php 14831 Bytes 16-07-2014 00:19:43
DIY 17 GHz Prescaler 1000:1
Prescaler up to 17 GHz with an HMC494 and a ADF4113
5 MHz ... 17 GHz
- 10 dBm ... + 10 dBm
POWER / CONSUMPTION
8 ... 24 V (DC), 120 mA
55 mm x 24 mm x 80 mm
This Prescaler is a handy Accessories to extend the Frequency Range of almost
any Counter to 17 GHz.
The Use of a HMC494 (Prescaler) in alliance with a ADF4113HV (PLL Circuit) and a ATTINY45/85-20PU allows a division rate of 1000.
Easy Reading assured !
✈ Circuit Description
The first stage is a HMC494 which divides the input signal by 8. It can handle a power range from approx. - 10 dBm up to + 10 dBm.
It has an 50 Ω termination inside. No protection was foreseen in order not to disturb the input impedance.
The next stage is a PLL-IC (ADF4113HV) which is
cheap and has the the ability to output the RF_IN divided by the Prescaler/Counter-value, which is set by an ATTINY45/85-20PU
The output of the pll-ic has TTL-level. It is decoupled via a 100 Ω resistor.
Left: 1GHz/1MHz, right: 17GHz/17MHz. Level was + 5 dBm.
✈ Power Consumption
As with any high frequency circuit, the power consumption is 'high'. The Hittite HMC494 consumes approx. 103 mA at 5 V supply.
Therefore, the pcb may be equipped with a switched regulator (TSR1-2450) as well as a linear regulator (good old 7805).
Amplifiers with high gain tend to oscillate. So does the pll-circuit. If no rf signal is present at the input, an internal amplifier oscillates at about 14 MHz.
✈ Printed Circuit Board
✈ BOM Partlist
Other parts may be used as well. This is just a proposal.
Distributor Partnumber Remarks
Farnell, 3mm, green
Farnell, 1696320 or Farnell, 1831821
In case you mayst need a programmeable prescaler (up to 18 GHz), you may kindly consider the remarkeable work of Dr. Thomas Baier, DG8SAQ and Andreas
Zimmermann, DH7AZ : "Variabel einstellbarer Vorteiler bis 18 GHz mit ADF41020", published in Funkamateur, 12/2015, p. 1293
In case you are interested on the subject "Urheberrecht im Internet" the same edition has an interesting article by Niels Gründel.
✈ Share your thoughts
✈ Nothing more to be seen below this point ? Maybe your browser blocks the facebook iframe.
✈ The webmaster does not read the comments regularly. Urgent questions should be send via email.