Istanbul — ''Relations between the Soviet Union and Turkey have gone through sunny and cloudy periods,'' Soviet Premier Nikolai Tikhonov told his Turkish hosts in Ankara Wednesday.
The Soviet premier's comment, viewed here as an indication of warming relations between the two neighboring countries, was echoed by Turkish Prime Minister Turgut Ozal, who pointed out that ''a stagnant period is now left behind.''
Soviet-Turkish relations have indeed been cool in the last few years. Mr. Tikhonov's visit is the first by a Soviet leader in nearly 10 years.
But the significance and implications of the visit have not had the same interpretations in Moscow and Ankara.
For Moscow, the importance of the visit and the talks is political. Tikhonov presented an attractive economic package to the Turks (''a nice Christmas present,'' in the words of a Western observer here) as a political investment for the future.
Turkey's emphasis is on economic cooperation. Mr. Ozal has openly said that the two countries have different systems and different views on many issues, but that they could cooperate in the economic field.
The concrete result of Tikhonov's visit was in fact the signing of three agreements, the main one being a 5-year trade accord (1986-90) worth $6 billion. This opens up new prospects for Turkish exports to the vast Soviet market.
Another agreement provides for a 10-year (1985-95) period of economic and technical cooperation, including industrial joint ventures.
One major project agreed upon is a natural gas pipeline that will become operational in 1987 and will eventually furnish a total of 6 billion cubic meters of gas to Turkey. The cost of this project, as well as a new power link between the Soviet Union and eastern Turkey, will be paid for by Turkey with export earnings and not hard currency.
On the political front, the talks in Ankara were just an exchange which the Turks found worthwhile. They expressed their views on their problems with Greece and on Cyprus, as well as on the Armenian question and terrorism (all sensitive issues for the Russians), and assured them that the military bases now under construction in eastern Turkey - near the Soviet border - are not to be used for purposes outside NATO defense - such as the United States Rapid Deployment Force.
The Soviets concentrated on disarmament, criticisms of US policy in Europe and the Mideast, and fears of a nuclear war (issues on which Turkey has so far followed the Western line).
In spite of Turkey's reserved atitude toward the Soviets, Western diplomatic circles have expressed concern - particularly about possible Turkish dependence on Soviet gas and energy in the future. Concern has also been voiced that increasing contacts betwen the two countries, even in the economic field, may in the long run, have some political impact on Turkey's political attitudes and its relations with the West.
This is ruled out by Turkish officials who still feel suspicious about the Soviets - a suspicion based on several factors:
* The general deterioration of East-West relations. Turkey, as a loyal member of NATO, has followed suit and adopted a reserved and sometimes critical attitude toward the Soviet Union (particularly on Afghanistan and Poland).
* Turkey also has suggested that the Soviets were behind some of the leftist terrorist activities during the three years of military rule.
Attempts by Soviet diplomats in the last few years to revive relations with Turkey and to renew contacts and exchanges encountered apathy and suspicion on the Turkish side.
Moscow did not give up, however, and waited for a more opportune time. The Russians renewed their efforts after observing some changes in their favor.
First, Turkey returned to civilian government. Prime Minister Ozal, although a conservative, is pushing Turkish economic development and the country therefore needs closer trade and economic ties with all nations.
Second, Turkey is facing difficulties in its economic (and in some cases political) ties with its Western allies. Both the European Community and the US have recently imposed restrictions on Turkish imports (mainly textiles) and the European Community has for political reasons refused to grant aid to Turkey. This has led Turkey to look for new markets to diversify its trade.
Third, Turkey is having problems with Greece while Greek Prime Minister Andreas Papandreou flirts with Moscow.
Against this backdrop, the Soviet suggestion of a visit to Turkey by Premier Tikhonov was favorable received by Ankara.
As noted political analyst Fahir Armaoglu sums up the present situation: ''So long as Turkey cannot find exactly what it expects from the West, the Soviets will have a place in Turkey's economic development. This might have some political implications. But Turkey is certainly capable of manipulating such results.''